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Kishnani PS, Seefried L, Dahir KM, Martos-Moreno GÁ, Linglart A, Petryk A, Mowrey WR, Fang S, Ozono K, Högler W, Rockman-Greenberg C. New insights into the landscape of ALPL gene variants in patients with hypophosphatasia from the Global HPP Registry. Am J Med Genet A 2024:e63781. [PMID: 38884565 DOI: 10.1002/ajmg.a.63781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 04/29/2024] [Accepted: 05/20/2024] [Indexed: 06/18/2024]
Abstract
Hypophosphatasia (HPP) is a rare, inherited metabolic disease characterized by low tissue-nonspecific alkaline phosphatase activity due to ALPL gene variants. We describe ALPL variants from the observational, prospective, multinational Global HPP Registry. Inclusion in the analysis required a diagnosis of HPP, low serum ALP activity, and ≥1 ALPL variant. Of 1176 patients enrolled as of September 2022, 814 met inclusion criteria in Europe (48.9%), North America (36.7%), Japan (10.2%), Australia (2.6%), and elsewhere (1.6%). Most patients (74.7%) had 1 ALPL variant; 25.3% had ≥2 variants. Nearly all patients (95.6%) had known disease-causing variants; 4.4% had variants of uncertain significance. Disease-causing variants were predominantly missense (770/1556 alleles). The most common variants were c.571G>A (102/1628 alleles), c.1250A>G (66/1628 alleles), and c.1559del (61/1628 alleles). Variant profiles were generally consistent, except in Japan, where a higher proportion of patients (68.7%) had ≥2 ALPL variants, likely because more had disease onset before age 6 months (53.0% vs. 10.1%-23.1% elsewhere). Frameshift mutations (61/164 alleles) and inframe deletions (7/164 alleles) were more common in Japan. Twenty-three novel variants were discovered, each in a single geographic region, predominantly Europe. Analyses confirmed previously known ALPL variants, identified novel variants, and characterized geographic variation in frequency and type of ALPL variants in a large population.
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Affiliation(s)
| | | | - Kathryn M Dahir
- Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Gabriel Ángel Martos-Moreno
- Hospital Infantil Universitario Niño Jesús, IIS La Princesa, Universidad Autónoma de Madrid, CIBERobn, ISCIII, Madrid, Spain
| | - Agnès Linglart
- Paris-Saclay University, AP-HP and INSERM, Paris, France
| | - Anna Petryk
- Alexion, AstraZeneca Rare Disease, Boston, Massachusetts, USA
| | | | - Shona Fang
- Alexion, AstraZeneca Rare Disease, Boston, Massachusetts, USA
| | - Keiichi Ozono
- Iseikai International General Hospital, Kita Ward, Osaka, Japan
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Heggie C, Al-Diwani H, Arundel P, Balmer R. Diagnosis and initial management of children presenting with premature loss of primary teeth associated with a systemic condition: A scoping review and development of clinical aid. Int J Paediatr Dent 2024. [PMID: 38609350 DOI: 10.1111/ipd.13188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 02/21/2024] [Accepted: 03/28/2024] [Indexed: 04/14/2024]
Abstract
BACKGROUND Premature loss of primary teeth (PLPT) can be a rare presentation of systemic medical conditions. Premature loss of primary teeth may present a diagnostic dilemma to paediatric dentists. AIMS To identify systemic conditions associated with PLPT and develop a clinical aid. DESIGN OVID Medline, Embase and Web of Science were searched up to March 2023. Citation searching of review publications occurred. Exclusion occurred for conference abstracts, absence of PLPT and absence of English-language full text. RESULTS Seven hundred and ninety-one publications were identified via databases and 476 by citation searching of review articles. Removal of 390 duplicates occurred. Following the exclusion of 466 records on abstract review, 411 publications were sought for retrieval, of which 142 met inclusion criteria. Thirty-one systemic conditions were identified. For 19 conditions, only one publication was identified. The majority of publications, 91% (n = 129), were case reports or series. Most publications, 44% (n = 62), were related to hypophosphatasia, and 25% (n = 35) were related to Papillon-Lefèvre. Diagnostic features were synthesised, and a clinical aid was produced by an iterative consensus approach. CONCLUSIONS A diverse range of systemic diseases are associated with PLPT. Evidence quality, however, is low, with most diseases having a low number of supporting cases. This clinical aid supports paediatric dentists in differential diagnosis and onward referral.
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Lee D, Park SY, Kim HS, Kang S. Short stature with low serum alkaline phosphatase activity: a case report of hypophosphatasia. Ann Pediatr Endocrinol Metab 2023; 28:312-317. [PMID: 38173385 PMCID: PMC10765032 DOI: 10.6065/apem.2244294.147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/06/2023] [Accepted: 04/20/2023] [Indexed: 01/05/2024] Open
Abstract
Hypophosphatasia (HPP) is a rare condition characterized by abnormal bone mineralization. The manifestations of HPP vary from no symptoms to intrauterine fetal death; short stature is another indication of HPP. A 3 ½-year-old boy presented with short stature, transient hypercalcemia, and mild gait disturbance without definite bony deformity. Laboratory examination revealed transient hypercalcemia, normal phosphorous and 25-hydroxy vitamin D levels, and mildly low alkaline phosphatase levels. A targeted next-generation sequencing panel associated with inborn errors of metabolism revealed a pathogenic heterozygous mutation in the ALPL gene, c.979T>C (p.Phe327Leu). When a child visits a hospital with short stature, decreased height velocity, and low alkaline phosphatase level, clinicians should consider the possibility of HPP even if definite skeletal dysplasia is not evident.
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Affiliation(s)
- Donghyun Lee
- Department of Pediatrics, Keimyung University Dongsan Hospital, Keimyung University School of Medicine, Daegu, Korea
| | - So Yun Park
- Department of Pediatrics, Keimyung University Dongsan Hospital, Keimyung University School of Medicine, Daegu, Korea
| | - Heung Sik Kim
- Department of Pediatrics, Keimyung University Daegu Dongsan Hospital, Daegu, Korea
| | - Seokjin Kang
- Department of Pediatrics, Keimyung University Dongsan Hospital, Keimyung University School of Medicine, Daegu, Korea
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Reis FS, Lazaretti-Castro M. Hypophosphatasia: from birth to adulthood. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2023; 67:e000626. [PMID: 37249457 PMCID: PMC10665056 DOI: 10.20945/2359-3997000000626] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 12/12/2022] [Indexed: 05/31/2023]
Abstract
Hypophosphatasia (HPP) is an inherited disease caused by a low activity of tissue-nonspecific alkaline phosphatase, a hydrolase that removes phosphate groups from many molecules. Decreased alkaline phosphatase activity leads to the accumulation of three main metabolites, i.e., pyridoxal 5´-phosphate (PLP), inorganic pyrophosphate (PPi), and phosphoethanolamine. Impairment in PLP dephosphorylation induces seizures, while PPi accumulation inhibits bone mineralization. Clinically, HPP has a wide spectrum of presentations, ranging from neonatal death to an apparent lack of symptoms. This disease is classified into six subtypes according to the age at onset of first signs or symptoms. The clinical manifestations of the disease include rickets-like bone changes, bone demineralization, fragility fractures, reduced muscular strength, chest deformity, pulmonary hypoplasia, nephrolithiasis, nephrocalcinosis, and chondrocalcinosis. Treatment of HPP consists of enzyme replacement therapy. Before this therapy was approved, treatment was palliative and associated with high morbidity and mortality. Asfotase alfa has changed the prognosis of the disease by reducing bone deformity and improving bone mineralization, lung function, and muscle weakness, among other benefits. In adults, teriparatide and anti-sclerostin antibody have been used off-label in selected cases, demonstrating benefit in accelerating fracture healing and in concomitant treatment of osteoporosis. This review summarizes the main aspects of HPP and identifies the particularities of the disease in adult patients.
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Affiliation(s)
- Fernanda Salles Reis
- Departamento de Medicina, Disciplina de Endocrinologia, Universidade Federal de São Paulo (Unifesp), São Paulo, Brasil
| | - Marise Lazaretti-Castro
- Departamento de Medicina, Disciplina de Endocrinologia, Universidade Federal de São Paulo (Unifesp), São Paulo, Brasil,
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Suzue M, Suga K, Teketani T, Nakagawa R, Urushihara M. Chylous ascites complicating perinatal severe hypophosphatasia in an infant on high-setting ventilation and enzyme replacement therapy. Pediatr Int 2023; 65:e15585. [PMID: 37475513 DOI: 10.1111/ped.15585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 05/16/2023] [Accepted: 05/31/2023] [Indexed: 07/22/2023]
Affiliation(s)
- Masashi Suzue
- Department of Pediatrics, Tokushima University Hospital, Tokushima, Japan
| | - Kenichi Suga
- Department of Pediatrics, Tokushima University Hospital, Tokushima, Japan
| | - Takeshi Teketani
- Department of Pediatrics, Shimane University Faculty of Medicine, Izumo, Japan
| | - Ryuji Nakagawa
- Department of Pediatrics, Tokushima University Hospital, Tokushima, Japan
| | - Maki Urushihara
- Department of Pediatrics, Tokushima University Hospital, Tokushima, Japan
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Feurstein J, Behanova M, Haschka J, Roetzer K, Uyanik G, Hadzimuratovic B, Witsch-Baumgartner M, Schett G, Zwerina J, Kocijan R. Identifying adult hypophosphatasia in the rheumatology unit. Orphanet J Rare Dis 2022; 17:435. [PMID: 36514157 PMCID: PMC9749273 DOI: 10.1186/s13023-022-02572-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 11/20/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The most frequent manifestation in adult hypophosphatasia (HPP) is musculoskeletal pain. The unspecific nature of its clinical presentation may prevent correct diagnosis. The aim of the study was to assess the prevalence of ALPL mutations in adult patients treated in rheumatological outpatient facilities with evident musculoskeletal symptoms typical for HPP. METHODS Over a period of 10 years 9,522 patients were screened in the rheumatology outpatient clinic of the Hanusch hospital Vienna. Serum ALP levels ≤ 40 U/L were found in 524 patients. After screening for secondary causes, 73 patients were invited for clinical evaluation. Genetic testing was performed in 23 patients with suspected HPP. Logistic regression models with Firth penalisation were used to estimate the unadjusted and BMI-adjusted association of each clinical factor with HPP. RESULTS Mutations in the ALPL gene were observed in 57% of genetically screened patients. Arthralgia, fractures, and pain were the leading symptoms in individuals with ALPL mutation. Chondrocalcinosis (OR 29.12; 95% CI 2.02-1593.52) and dental disease (OR 8.33; 95% CI 0.93-143.40) were associated with ALPL mutation, independent of BMI. Onset of symptoms in patients with ALPL mutation was at 35.1 (14.3) years, with a mean duration from symptoms to diagnosis of 14.4 (8.1) years. Bone mineral density (BMD) and trabecular bone score (TBS) as well as bone turnover markers were not indicative for HPP or ALPL mutation. CONCLUSION HPP can mimic rheumatologic diseases. Thus, HPP should be considered as a possible diagnosis in adult patients presenting with musculoskeletal pain of unknown origin in rheumatology outpatient clinics. In patients with persistently low ALP serum levels and unclear musculoskeletal pain, HPP as the underlying cause has to be considered.
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Affiliation(s)
- Julia Feurstein
- grid.413662.40000 0000 8987 0344Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1St Medical Department, Hanusch Hospital, Heinrich-Collin-Strasse 30, 1140 Vienna, Austria ,grid.413662.40000 0000 8987 03441St Medical Department, Hanusch Hospital Vienna, Vienna, Austria
| | - Martina Behanova
- grid.413662.40000 0000 8987 0344Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1St Medical Department, Hanusch Hospital, Heinrich-Collin-Strasse 30, 1140 Vienna, Austria
| | - Judith Haschka
- grid.413662.40000 0000 8987 0344Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1St Medical Department, Hanusch Hospital, Heinrich-Collin-Strasse 30, 1140 Vienna, Austria ,grid.413662.40000 0000 8987 03441St Medical Department, Hanusch Hospital Vienna, Vienna, Austria ,Vienna Bone and Growth Centre, Vienna, Austria
| | - Katharina Roetzer
- grid.413662.40000 0000 8987 0344Centre for Medical Genetics, Hanusch Hospital Vienna, Vienna, Austria ,grid.263618.80000 0004 0367 8888Medical Faculty of Genetics, Sigmund Freud University, Vienna, Austria
| | - Gökhan Uyanik
- grid.413662.40000 0000 8987 0344Centre for Medical Genetics, Hanusch Hospital Vienna, Vienna, Austria ,grid.263618.80000 0004 0367 8888Medical Faculty of Genetics, Sigmund Freud University, Vienna, Austria
| | - Benjamin Hadzimuratovic
- grid.413662.40000 0000 8987 03441St Medical Department, Hanusch Hospital Vienna, Vienna, Austria
| | - Martina Witsch-Baumgartner
- grid.5361.10000 0000 8853 2677Division Human Genetics, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University Innsbruck, Innsbruck, Austria
| | - Georg Schett
- grid.5330.50000 0001 2107 3311Department of Internal Medicine 3, The University Clinic of Erlangen, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Jochen Zwerina
- grid.413662.40000 0000 8987 0344Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1St Medical Department, Hanusch Hospital, Heinrich-Collin-Strasse 30, 1140 Vienna, Austria ,grid.413662.40000 0000 8987 03441St Medical Department, Hanusch Hospital Vienna, Vienna, Austria ,Vienna Bone and Growth Centre, Vienna, Austria
| | - Roland Kocijan
- grid.413662.40000 0000 8987 0344Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1St Medical Department, Hanusch Hospital, Heinrich-Collin-Strasse 30, 1140 Vienna, Austria ,grid.413662.40000 0000 8987 03441St Medical Department, Hanusch Hospital Vienna, Vienna, Austria ,Vienna Bone and Growth Centre, Vienna, Austria ,grid.263618.80000 0004 0367 8888Medical Faculty of Bone Diseases, Sigmund Freud University, Vienna, Austria
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Okawa R, Nakano K. Dental manifestation and management of hypophosphatasia. JAPANESE DENTAL SCIENCE REVIEW 2022; 58:208-216. [PMID: 35814738 PMCID: PMC9260292 DOI: 10.1016/j.jdsr.2022.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/22/2022] [Accepted: 06/26/2022] [Indexed: 11/24/2022] Open
Abstract
Hypophosphatasia is an inherited metabolic disorder characterized by defective mineralization of bones and teeth with a wide variety of manifestations, ranging from stillbirth to dental symptoms alone. Recently, the prognosis of severe hypophosphatasia patients has been greatly improved by the introduction of enzyme replacement therapy. The typical dental manifestation is early exfoliation of primary teeth due to disturbed cementum formation, so dentures are recommended to ensure that important oral functions are acquired. Some studies have shown that enzyme replacement therapy improves dental mineralization, resulting in the stabilization of periodontal tissues and better growth of tooth roots. A nationwide Japanese survey revealed the common genetic and dental manifestations of patients with mild hypophosphatasia, which markedly differ from those of the severe forms. There may be many undiagnosed mild patients, so dentists should contribute to the early diagnosis by screening possible cases based on the typical finding of early exfoliation of primary teeth. Early diagnosis is important for patients to receive early intervention in both medical and dental fields. The establishment of fundamental dental therapy to solve the dental problems is still underway and is eagerly anticipated.
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Two children with hypophosphatasia with a heterozygous c.1559delT variant in the ALPL gene, the most common variant in Japanese populations. Bone Rep 2022; 17:101626. [PMID: 36217348 PMCID: PMC9547180 DOI: 10.1016/j.bonr.2022.101626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 09/29/2022] [Accepted: 10/02/2022] [Indexed: 11/07/2022] Open
Abstract
Hypophosphatasia (HPP), a genetic disorder characterized by decreased tissue-nonspecific alkaline phosphatase (TNSALP) activity, is caused by loss-of-function mutations in the ALPL gene, which encodes TNSALP. The most frequent pathogenic variant in Japanese patients with HPP is a frameshift mutation in the ALPL gene, c.1559delT, and its carrier frequency is reported to be one in 480 in the Japanese population. We report the cases of two Japanese children with HPP who had a heterozygous c.1559delT variant in the ALPL gene. One case (involving a neonate) exhibited respiratory insufficiency associated with vitamin B6 dependent convulsions, significant defective mineralization similar to the severe form of HPP, and extremely low ALP activity. Enzyme replacement therapy (ERT) using asfotase alfa promptly improved her respiratory insufficiency, bone mineralization, and maintained her motor development during infancy. The second case involved a 10-year-old boy who demonstrated diffuse musculoskeletal pain and weakness that progressively disturbed mobility. Although he showed no bony lesions, the clinical symptoms and biochemical abnormalities were compatible with childhood HPP. ERT successfully relieved the severe generalized pain and significantly improved motor function. A heterozygous c.1559delT in ALPL is the most frequent variant in Japanese populations, with aprevalence of 1/480. Two Japanese children with this variant developed hypophosphatasia associated with a low serum alkaline phosphatase. One neonate showed respiratory insufficiency and defective bone mineralization similar to the severe form of HPP. The other 10-year-old boy demonstrated diffuse musculoskeletal pain and weakness that progressively disturbed mobility. Enzyme replacement therapy successfully improved pathological symptoms in both cases.
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Chinoy A, Iruloh C, Kerr B, Mughal MZ, Padidela R. Normal Mid-Gestation Fetal Ultrasonography Cannot Reliably Exclude Severe Perinatal Hypophosphatasia. Horm Res Paediatr 2022; 94:307-312. [PMID: 34438404 DOI: 10.1159/000519209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 07/22/2021] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Hypophosphatasia is a systemic bone disease characterized by inhibition of bone mineralization due to mutations in the ALPL gene that results in a deficiency of tissue nonspecific alkaline phosphatase. The perinatal form is the most severe. In the past, this form was lethal, although human recombinant enzyme replacement therapy has now been developed and licensed, which improves survival. Perinatal hypophosphatasia is usually suggested on antenatal ultrasonography with undermineralization of the long bones, skull, and thoracic cavity. In the UK, antenatal ultrasonography for fetal anomalies is conducted at mid-gestation (i.e., 18-21 weeks gestational age), and if normal, no further routine scans are performed. Usually, this would identify abnormalities in bone mineralization suggestive of perinatal hypophosphatasia. CASES We describe 2 cases of perinatal hypophosphatasia where mid-gestation ultrasonography was normal. In the first case, where a previous pregnancy had been terminated for perinatal hypophosphatasia, third trimester ultrasonography revealed skeletal features of hypophosphatasia. In the second case, the diagnosis of perinatal hypophosphatasia was made only immediately after birth. CONCLUSION We conclude that serial antenatal ultrasonography or antenatal genetic testing should be considered in all pregnancies with a positive family history of hypophosphatasia, as mid-gestation ultrasonography cannot reliably exclude perinatal hypophosphatasia. This is especially important given that effective enzyme replacement therapy is now available.
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Affiliation(s)
- Amish Chinoy
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester, United Kingdom.,Faculty of Biology, Medicine & Health, University of Manchester, Manchester, United Kingdom
| | - Chibuike Iruloh
- Fetal Medicine Unit, St. Mary's Hospital, Manchester, United Kingdom
| | - Bronwyn Kerr
- Division of Evolution and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - M Zulf Mughal
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester, United Kingdom.,Faculty of Biology, Medicine & Health, University of Manchester, Manchester, United Kingdom
| | - Raja Padidela
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester, United Kingdom.,Faculty of Biology, Medicine & Health, University of Manchester, Manchester, United Kingdom
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Jaruga A, Ksiazkiewicz J, Kuzniarz K, Tylzanowski P. Orofacial Cleft and Mandibular Prognathism-Human Genetics and Animal Models. Int J Mol Sci 2022; 23:ijms23020953. [PMID: 35055138 PMCID: PMC8779325 DOI: 10.3390/ijms23020953] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/24/2021] [Accepted: 01/13/2022] [Indexed: 12/12/2022] Open
Abstract
Many complex molecular interactions are involved in the process of craniofacial development. Consequently, the network is sensitive to genetic mutations that may result in congenital malformations of varying severity. The most common birth anomalies within the head and neck are orofacial clefts (OFCs) and prognathism. Orofacial clefts are disorders with a range of phenotypes such as the cleft of the lip with or without cleft palate and isolated form of cleft palate with unilateral and bilateral variations. They may occur as an isolated abnormality (nonsyndromic-NSCLP) or coexist with syndromic disorders. Another cause of malformations, prognathism or skeletal class III malocclusion, is characterized by the disproportionate overgrowth of the mandible with or without the hypoplasia of maxilla. Both syndromes may be caused by the presence of environmental factors, but the majority of them are hereditary. Several mutations are linked to those phenotypes. In this review, we summarize the current knowledge regarding the genetics of those phenotypes and describe genotype-phenotype correlations. We then present the animal models used to study these defects.
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Affiliation(s)
- Anna Jaruga
- Laboratory of Molecular Genetics, Department of Biomedical Sciences, Medical University of Lublin, Chodzki 1, 20-093 Lublin, Poland; (A.J.); (J.K.)
| | - Jakub Ksiazkiewicz
- Laboratory of Molecular Genetics, Department of Biomedical Sciences, Medical University of Lublin, Chodzki 1, 20-093 Lublin, Poland; (A.J.); (J.K.)
- Center for Molecular and Vascular Biology, Department of Cardiovascular Sciences, University of Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Krystian Kuzniarz
- Department of Maxillofacial Surgery, Medical University of Lublin, Staszica 11, 20-081 Lublin, Poland;
| | - Przemko Tylzanowski
- Laboratory of Molecular Genetics, Department of Biomedical Sciences, Medical University of Lublin, Chodzki 1, 20-093 Lublin, Poland; (A.J.); (J.K.)
- Department of Development and Regeneration, University of Leuven, Herestraat 49, 3000 Leuven, Belgium
- Correspondence:
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Abstract
Hypophosphatasia (HPP) is an inherited metabolic disease caused by loss-of-function mutations in the tissue non-specific alkaline phosphatase (TNAP) gene. Reduced activity of TNAP leads to the accumulation of its substrates, mainly inorganic pyrophosphate and pyridoxal-5′-phosphate, metabolic aberrations that largely explain the musculoskeletal and systemic features of the disease. More than 400 ALPL mutations, mostly missense, are reported to date, transmitted by either autosomal dominant or recessive mode. Severe disease is rare, with incidence ranging from 1:100,000 to 1:300,000 live births, while the estimated prevalence of the less severe adult form is estimated to be between 1:3100 to 1:508, in different countries in Europe. Presentation largely varies, ranging from death in utero to asymptomatic adults. In infants and children, clinical features include skeletal, respiratory and neurologic complications, while recurrent, poorly healing fractures, muscle weakness and arthropathy are common in adults. Persistently low serum alkaline phosphatase is the cardinal biochemical feature of the disease. Management requires a dedicated multidisciplinary team. In mild cases, treatment is usually symptomatic. Severe cases, with life-threating or debilitating complications, can be successfully treated with enzyme replacement therapy with asfotase alfa.
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Hasegawa A, Nakamura-Takahashi A, Kasahara M, Saso N, Narisawa S, Millán JL, Samura O, Sago H, Okamoto A, Umezawa A. Prenatal enzyme replacement therapy for Akp2 -/- mice with lethal hypophosphatasia. Regen Ther 2021; 18:168-175. [PMID: 34277899 PMCID: PMC8267436 DOI: 10.1016/j.reth.2021.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/28/2021] [Accepted: 06/06/2021] [Indexed: 11/21/2022] Open
Abstract
Hypophosphatasia (HPP) is a congenital skeletal disease. Impairment of bone mineralization and seizures are due to a deficiency of tissue-nonspecific alkaline phosphatase (TNAP). Enzyme replacement therapy (ERT) is available as a highly successful treatment for pediatric-onset HPP. However, the potential for prenatal ERT has not been fully investigated to date. In this study, we assessed outcomes and maternal safety using a combinational approach with prenatal and postnatal administration of recombinant TNAP in Akp2−/− mice as a model of infantile HPP. For the prenatal ERT, we administered subcutaneous injections of recombinant TNAP to pregnant mice from embryonic day 11.5–14.5 until delivery, and then sequentially to Akp2−/− pups from birth to day 18. For the postnatal ERT, we injected Akp2−/− pups from birth until day 18. Prenatal ERT did not cause any ectopic mineralization in heterozygous maternal mice. Both prenatal and postnatal ERT preserved growth, survival rate and improved bone calcification in Akp2−/− mice. However, the effects of additional prenatal treatment to newborn mice appeared to be minimal, and the difference between prenatal and postnatal ERT was subtle. Further improvement of the prenatal ERT schedule and long-term observation will be required. The present paper sets a standard for such future studies.
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Affiliation(s)
- Akihiro Hasegawa
- Center for Regenerative Medicine, National Center for Child Health and Development Research Institute, Tokyo, Japan.,Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | | | | | - Nana Saso
- Center for Regenerative Medicine, National Center for Child Health and Development Research Institute, Tokyo, Japan
| | - Sonoko Narisawa
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - José Luis Millán
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Osamu Samura
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Haruhiko Sago
- Center for Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Tokyo, Japan
| | - Aikou Okamoto
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Akihiro Umezawa
- Center for Regenerative Medicine, National Center for Child Health and Development Research Institute, Tokyo, Japan
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İnci A, Ergin FBC, Yüce BT, Çiftçi B, Demir E, Buyan N, Okur İ, Biberoğlu G, Öktem RM, Tümer L, Ezgü FS. Hypophosphatasia: is it an underdiagnosed disease even by expert physicians? J Bone Miner Metab 2021; 39:598-605. [PMID: 33404770 DOI: 10.1007/s00774-020-01193-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 12/06/2020] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Hypophosphatasia (HPP) is caused by mutations in the ALPL that encodes the tissue-nonspecific isoenzyme of alkaline phosphatase (ALP). Clinical manifestations range from extreme life-threatening lethal forms to no signs or symptoms at all. MATERIALS AND METHODS Consecutive 30,000 outpatients and inpatients with ALP data were screened retrospectively, out of which 1000 patients were found to have low levels of ALP more than once. Then, patients were evaluated for the symptoms and signs of HPP with further biochemical and genetic analyses. RESULTS Thirty-seven patients who had severe musculoskeletal pain, recurrent fractures, and tooth anomalies were then screened with substrate and DNA sequencing analyses for HPP. It was determined that eight patients had variants in the ALPL gene. A total of eight different ALPL variants were identified in eight patients. The variants, namely c.244G > C (p.Gly82Arg), c.1444C > T (p.His482Tyr), c.1487A > G (p.Asn493Ser), and c.675_676insCA (p.Met226GlnfsTer52), had not been previously reported. DISCUSSION Considering the wide spectrum of clinical signs and symptoms, HPP should be among the differential lists of bone, muscle, and tooth abnormalities at any age.
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Affiliation(s)
- Aslı İnci
- Department of Pediatric Metabolism, Gazi University School of Medicine, 06500, Beşevler, Ankara, Turkey.
| | - Filiz Başak Cengiz Ergin
- Department of Pediatric Metabolism, Gazi University School of Medicine, 06500, Beşevler, Ankara, Turkey
| | - Burcu Topcu Yüce
- Department of Pediatric Metabolism, Gazi University School of Medicine, 06500, Beşevler, Ankara, Turkey
| | - Bahattin Çiftçi
- Department of Pediatric Metabolism, Gazi University School of Medicine, 06500, Beşevler, Ankara, Turkey
| | - Ercan Demir
- Department of Pediatric Neurology, Gazi University School of Medicine, 06500, Beşevler, Ankara, Turkey
| | - Necla Buyan
- Department of Pediatric Nephrology, Gazi University School of Medicine, 06500, Beşevler, Ankara, Turkey
| | - İlyas Okur
- Department of Pediatric Metabolism, Gazi University School of Medicine, 06500, Beşevler, Ankara, Turkey
| | - Gürsel Biberoğlu
- Department of Pediatric Metabolism, Gazi University School of Medicine, 06500, Beşevler, Ankara, Turkey
| | - Rıdvan Murat Öktem
- Department of Pediatric Metabolism, Gazi University School of Medicine, 06500, Beşevler, Ankara, Turkey
| | - Leyla Tümer
- Department of Pediatric Metabolism, Gazi University School of Medicine, 06500, Beşevler, Ankara, Turkey
| | - Fatih Süheyl Ezgü
- Department of Pediatric Metabolism, Gazi University School of Medicine, 06500, Beşevler, Ankara, Turkey
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14
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An 8-month-old infant with hypercalcemia and hyperphosphatemia-Answers. Pediatr Nephrol 2021; 36:563-566. [PMID: 32588225 DOI: 10.1007/s00467-020-04666-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 06/04/2020] [Accepted: 06/08/2020] [Indexed: 10/24/2022]
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15
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Estimation of the carrier frequencies and proportions of potential patients by detecting causative gene variants associated with autosomal recessive bone dysplasia using a whole-genome reference panel of Japanese individuals. Hum Genome Var 2021; 8:2. [PMID: 33452237 PMCID: PMC7810679 DOI: 10.1038/s41439-020-00133-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 12/04/2022] Open
Abstract
Bone dysplasias are a group of rare hereditary diseases, with up to 436 disease types. Perinatal diagnosis is clinically important for adequate personalized management and counseling. There are no reports focused on pathogenic variants of bone dysplasias in the general population. In this study, we focused on autosomal recessive bone dysplasias. We identified pathogenic variants using whole-genome reference panel data from 3552 Japanese individuals. For the first time, we were able to estimate the carrier frequencies and the proportions of potential patients. For autosomal recessive bone dysplasias, we detected 198 pathogenic variants of 54 causative genes. We estimated the variant carrier frequencies and the proportions of potential patients with variants associated with four clinically important bone dysplasias: osteogenesis imperfecta (OI), hypophosphatasia (HPP), asphyxiating thoracic dysplasia (ATD), and Ellis–van Creveld syndrome (EvC). The proportions of potential patients with OI, ATD, and EvC based on pathogenic variants classified as “pathogenic” and “likely pathogenic” by InterVar were closer to the reported incidence rates in Japanese subjects. Furthermore, the proportions of potential patients with HPP variants classified as “pathogenic” and “likely pathogenic” in InterVar and “pathogenic” in ClinVar were closer to the reported incidence rates. For bone dysplasia, the findings of this study will provide a better understanding of the variant types and frequencies in the Japanese general population, and should be useful for clinical diagnosis, genetic counseling, and personalized medicine. A bioinformatics approach helps estimate carrier frequency of a rare inherited bone disease which causes abnormalities in skeletal shape and structure. Autosomal recessive bone dysplasias affect bone and cartilage development and result from inheriting two mutated genes, one from each parent. Junichi Sugawara, Tohoku University, Sendai, Japan, and colleagues used mutation databases and a bioinformatics tool for variant interpretation to detect 198 pathogenic variants in 54 genes associated with autosomal recessive bone dysplasia in a whole-genome reference panel of 3,552 general Japanese individuals (3.5KJPNv2). They then estimated the frequency of people in the sample carrying bone dysplasia mutations and the expected proportion in whom the disorder could manifest, which compared well with reported incidence rates in the general population. These findings could prove useful for calculating the risk of bone dysplasia in the future children of carrier parents.
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Matsuda N, Takasawa K, Ohata Y, Takishima S, Kubota T, Ishihara Y, Fujiwara M, Ogawa E, Morio T, Kashimada K, Ozono K. Potential pathological role of single nucleotide polymorphism (c.787T>C) in alkaline phosphatase (ALPL) for the phenotypes of hypophosphatasia. Endocr J 2020; 67:1227-1232. [PMID: 32779619 DOI: 10.1507/endocrj.ej20-0203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Hypophosphatasia (HPP; OMIM 241510, 241500, and 146300) is an inherited metabolic disease characterized by defects of bone and tooth mineralization, which is caused by loss-of-function mutations in the ALPL gene encoding tissue non-specific alkaline phosphatase (TNSALP). In the last three decades, several studies have focused on the genotype-phenotype correlation in hypophosphatasia (HPP). In particular, functional tests based on in vitro analysis for the residual enzymatic activities of mutations have revealed a clear but imperfect genotype-phenotype correlation, suggesting that multiple potential factors modulate the phenotype. One of the missense variants identified in the tissue non-specific alkaline phosphatase (ALPL) gene, c.787T>C, has been considered as a benign polymorphism in HPP; however, its pathogenicity and role in disease manifestation remain controversial. We here report our recent experience of three unrelated families harboring the c.787T>C variant, suggesting clinical implications regarding the controversial pathogenicity of c.787T>C. First, despite the lack of obvious clinical phenotypes, homozygous c.787T>C would decrease the serum level of ALP activity. Second, c.787T>C might deteriorate phenotypes of a patient harboring another ALPL variant, especially one that has thus far presumed to be benign, e.g., the c.1144G>A variant. These cases contribute to the recent advances in understanding HPP to facilitate clinical recognition of more subtle phenotypes, further providing insights into the pathogenesis of HPP.
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Affiliation(s)
- Nozomi Matsuda
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
- Department of Pediatrics, Soka Municipal Hospital, Saitama 340-8560, Japan
| | - Kei Takasawa
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
| | - Yasuhisa Ohata
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Shigeru Takishima
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
- Department of Pediatrics, Soka Municipal Hospital, Saitama 340-8560, Japan
| | - Takuo Kubota
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Yasuki Ishihara
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
- The first Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Osaka 565-0871, Japan
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Makoto Fujiwara
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
- The first Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Osaka 565-0871, Japan
| | - Erika Ogawa
- Department of Pediatrics and Child Health, Nihon University School of Medicine, Tokyo 101-8309, Japan
| | - Tomohiro Morio
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
| | - Kenichi Kashimada
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
| | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
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Kato M, Hattori T, Shimizu T, Ninagawa K, Izumihara R, Nomoto H, Tanimura K, Atsumi T. Intrafamilial phenotypic distinction of hypophosphatasia with identical tissue nonspecific alkaline phosphatase gene mutation: a family report. J Bone Miner Metab 2020; 38:903-907. [PMID: 32772198 DOI: 10.1007/s00774-020-01137-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 07/30/2020] [Indexed: 10/23/2022]
Abstract
Hypophosphatasia (HPP) is caused by mutations in the tissue nonspecific alkaline phosphatase (TNSALP) gene in an autosomal recessive or dominant manner and characterized by defective mineralization of bone and low serum ALP levels. In this report, we present a family with HPP mother (case 1) and HPP child (case 2) who have identical TNSALP gene mutation (c.1015G>A p.Gly339Arg heterozygous mutation) but distinct clinical phenotypes. Whereas case 1 appeared to be asymptomatic despite extremely low levels of serum ALP, case 2 had several HPP-related symptoms, such as tooth loss, fractures, short stature, with slightly decreased ALP levels. Upon the diagnosis of HPP, case 1 discontinued denosumab, which was used to treat her rheumatoid arthritis, concerning the risk of atypical femoral fractures. The clinical course of this family was suggestive in a genotype-phenotype imbalance in HPP, the underdiagnosis of HPP in adults, and the risk of atypical femoral fractures using bone resorption inhibitors.
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Affiliation(s)
- Masaru Kato
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, N15W7, Kita-Ku, Sapporo, 060-8638, Japan.
| | | | - Tomohiro Shimizu
- Department of Orthopedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Keita Ninagawa
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, N15W7, Kita-Ku, Sapporo, 060-8638, Japan
| | - Rimi Izumihara
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, N15W7, Kita-Ku, Sapporo, 060-8638, Japan
| | - Hiroshi Nomoto
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, N15W7, Kita-Ku, Sapporo, 060-8638, Japan
| | | | - Tatsuya Atsumi
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, N15W7, Kita-Ku, Sapporo, 060-8638, Japan
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18
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Tilden DR, Sheehan JH, Newman JH, Meiler J, Capra JA, Ramirez A, Simmons J, Dahir K. Phenotypic Profiling in Subjects Heterozygous for 1 of 2 Rare Variants in the Hypophosphatasia Gene ( ALPL). J Endocr Soc 2020; 4:bvaa084. [PMID: 32803091 PMCID: PMC7417882 DOI: 10.1210/jendso/bvaa084] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 06/22/2020] [Indexed: 11/19/2022] Open
Abstract
Context Hypophosphatasia (HPP) is a syndrome marked by low serum alkaline phosphatase (AlkP) activity as well as musculoskeletal and/or dental disease. While the majority of subjects with HPP carry a pathogenic variant in the ALPL gene or its regulatory regions, individual pathogenic variants are often not tightly correlated with clinical symptomatology. We sought to better understand the genotype/phenotype correlation in HPP by examining the clinical and biochemical data of 37 subjects with 2 rare variants in ALPL. Methods Through BioVU, a DNA biobank that pairs individuals’ genetic information with their de-identified medical records, we identified subjects with 2 rare variants with distinct reported clinical phenotypes (p.D294A and p.T273M). We then performed a manual review of these subjects’ de-identified medical records along with computational modeling of protein structure to construct a genetic, biochemical and clinical phenotype for each subject and variant. Results Twenty subjects with the p.D294A variant and 17 with the p.T273M variant had sufficient data for analysis. Among subjects in our cohort with the p.D294A variant, 6 (30.0%) had both clinical bone disease and serum AlkP activity below 40 IU/L while 4 subjects (23.5%) with the p.T273M variant met the same criteria despite the distinct clinical phenotypes of these variants. Conclusions Given the loose genotype/phenotype correlation in HPP seen in our cohort, clinical context is crucial for the interpretation of genetic test results to guide clinical care in this population. Otherwise, over- or under-diagnosis may occur, resulting in misidentification of those who may benefit from additional screening and perhaps pharmacologic intervention.
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Affiliation(s)
- Daniel R Tilden
- Division of Endocrinology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee.,Ian M. Burr Division of Pediatric Endocrinology, Department of Pediatrics, Monroe Carroll Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee
| | - Jonathan H Sheehan
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - John H Newman
- Division of Allergy, Pulmonary and Critical Care Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jens Meiler
- Center for Structural Biology, Vanderbilt University Medical Center Nashville, TN.,Department of Chemistry, Vanderbilt University Medical Center, Nashville, Tennessee.,Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - John A Capra
- Center for Structural Biology, Vanderbilt University Medical Center Nashville, TN.,Department of Chemistry, Vanderbilt University Medical Center, Nashville, Tennessee.,Department of Biological Sciences and Biomedical Informatics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Andrea Ramirez
- Division of Endocrinology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jill Simmons
- Ian M. Burr Division of Pediatric Endocrinology, Department of Pediatrics, Monroe Carroll Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee
| | - Kathryn Dahir
- Division of Endocrinology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
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19
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Chida-Naomiya R, Shimura M, Nagao R, Kumada A, Kawashima H. Hearing impairment improved after treatment with asfotase alfa in a case of perinatal hypophosphatasia. Mol Genet Metab Rep 2020; 24:100612. [PMID: 32547926 PMCID: PMC7284058 DOI: 10.1016/j.ymgmr.2020.100612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/25/2020] [Accepted: 05/25/2020] [Indexed: 01/07/2023] Open
Abstract
Hearing impairment is a neurological symptom of hypophosphatasia (HPP), which leads to a reduced quality of life. However, the pathomechanism of hearing impairment and the effects of asfotase alfa enzyme replacement therapy on hearing function in HPP have not been clarified. Here we report a case and present clinical data of a patient with perinatal HPP whose hearing impairment improved after asfotase alfa treatment.
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Affiliation(s)
- Rie Chida-Naomiya
- Department of Pediatrics and Adolescent Medicine, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160-0023, Japan
| | - Masaru Shimura
- Department of Pediatrics and Adolescent Medicine, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160-0023, Japan
| | - Ryuhei Nagao
- Department of Pediatrics and Adolescent Medicine, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160-0023, Japan
| | - Atsushi Kumada
- Department of Pediatrics and Adolescent Medicine, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160-0023, Japan
| | - Hisashi Kawashima
- Department of Pediatrics and Adolescent Medicine, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160-0023, Japan
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20
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Koyama H, Yasuda S, Kakoi S, Ohata Y, Shimizu Y, Hasegawa C, Hayakawa A, Akiyama T, Yagi T, Aotani D, Imaeda K, Ozono K, Kataoka H, Tanaka T. Effect of Asfotase Alfa on Muscle Weakness in a Japanese Adult Patient of Hypophosphatasia with Low ALP Levels. Intern Med 2020; 59:811-815. [PMID: 31787692 PMCID: PMC7118397 DOI: 10.2169/internalmedicine.3298-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
A 40-year-old Japanese woman presented to our hospital with general fatigue and muscle weakness. She had a history of premature loss of deciduous teeth at 4 years old, her serum alkaline phosphatase (ALP) activity was as low as 91 U/L, and radiologic studies revealed thoracic deformity and sacroiliac calcification. Genetic sequencing revealed a heterozygous c.1559delT mutation in the tissue non-specific alkaline phosphatase gene (ALPL). Based on these findings, she was diagnosed with hypophosphatasia (HPP), and treatment with asfotase alfa, a recombinant human tissue-nonspecific alkaline phosphatase (TNSALP), was initiated. After six months of treatment with asfotase alfa, improvements were observed in the SF-36 score, six-minute walk distance, and grasping power. Although the overdiagnosis needs to be avoided, HPP should be considered in patients with undiagnosed musculoskeletal symptoms and a low serum ALP activity.
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Affiliation(s)
- Hiroyuki Koyama
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Science, Japan
| | - Satoshi Yasuda
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Science, Japan
| | - Shota Kakoi
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Science, Japan
| | - Yasuhisa Ohata
- Department of Pediatrics, Osaka University Graduate School of Medicine, Japan
| | - Yuki Shimizu
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Science, Japan
| | - Chie Hasegawa
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Science, Japan
| | - Akiko Hayakawa
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Science, Japan
| | - Tomoyuki Akiyama
- Department of Child Neurology, Okayama University Graduate School of Medicine, Japan
| | - Takashi Yagi
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Science, Japan
| | - Daisuke Aotani
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Science, Japan
| | - Kenro Imaeda
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Science, Japan
- Department of Endocrinology and Diabetes, Nagoya City West Medical Center, Japan
| | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, Japan
| | - Hiromi Kataoka
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Science, Japan
| | - Tomohiro Tanaka
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Science, Japan
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21
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Abstract
Hypophosphatasia (HPP) is a rare inherited systemic metabolic disease caused by mutations in the tissue-nonspecific alkaline phosphatase (TNSALP) gene. TNSALP is expressed in the liver, kidney and bone, and its substrates include TNSALP inorganic pyrophosphate, pyridoxal-5'-phosphate (PLP)/vitamin B6 and phosphoethanolamine (PEA). Autosomal recessive and dominant forms of the disease result in a range of clinical entities. Major hallmarks are low alkaline phosphatase (ALP) and elevated PLP and PEA levels. Very severe infantile forms of HPP cause premature death as a result of respiratory insufficiency and also present with hypo-mineralisation leading to deformed limbs with, in some cases, the near-absence of bones and skull altogether. Respiratory failure, rib fractures and seizures due to vitamin B6 deficiency are indicative of a poor prognosis. Craniosynostosis is frequent. HPP leads to an unusual presentation of rickets with high levels of calcium and phosphorus, resulting in hypercalciuria, nephrocalcinosis and low ALP levels. Hypercalcaemic crisis, failure to thrive and growth retardation are concerns in infants. Fractures are common in both infantile and adult forms of the disease, concomitantly occurring with unexplained chronic pain and fatigue. Dental clinical presentations, which include the premature loss of teeth, are also commonly found in HPP and specifically manifest as odontohypophosphatasia. A novel enzyme therapy for human HPP, asfotase alfa, which is specifically targeted to mineralised tissues, has been developed in the past decades. While this treatment seems very promising, especially for infantile HPP, many questions regarding its long-term effects, the management of treatment, and any potential secondary adverse effects remain unresolved.
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22
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Association of ALPL variants with serum alkaline phosphatase and bone traits in the general Japanese population: The Nagahama Study. J Hum Genet 2019; 65:337-343. [PMID: 31857675 DOI: 10.1038/s10038-019-0712-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/28/2019] [Accepted: 12/12/2019] [Indexed: 12/21/2022]
Abstract
Although alkaline phosphatase (ALP) activity is relatively low in carriers of recessive type hypophosphatasia (HPP), most are asymptomatic and therefore do not undergo medical evaluations. We analyzed the association of ALP-encoding ALPL variants with serum ALP and bone traits in the general Japanese population. Study participants (n = 9671) were from the Nagahama Study, which was a longitudinal cohort study of an apparently healthy general Japanese population. ALPL variants were analyzed by whole-genome sequencing or TaqMan probe assays using DNA extracted from peripheral blood samples. The speed of sound in calcaneal bone was assessed by quantitative ultrasound (QUS) and used as surrogate measures of bone mineral density. We identified 13 ALPL variants. Minor allele frequencies of three variants were higher than expected. Variant c.529G > A has been reported as a possible pathogenic variant for adult type HPP. Variants c.979C > T and c.1559delT are reported as pathogenic variants for perinatal severe HPP or infantile HPP. The allele frequencies of c.529G > A, c.979C > T, and c.1559delT were 0.0107, 0.0040, and 0.0014, respectively. Serum ALP activity was significantly lower and differed among the three variants (P < 0.001), as well as between individuals with and without any of the three variants (P < 0.001). Serum ALP activity was inversely associated with QUS values, although no direct association was observed between the ALPL variants and QUS values. An association between serum ALP activity and QUS was confirmed; however, we failed to detect an association between ALPL variants and bone traits in the general Japanese population.
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Hypophosphatasie – eine klinisch und genetisch variable Erkrankung. MED GENET-BERLIN 2019. [DOI: 10.1007/s11825-019-00271-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Zusammenfassung
Die Hypophosphatasie (HPP) ist eine erbliche metabolische Multisystemerkrankung, deren klinische Hauptcharakteristika Mineralisierungsstörungen von Knochen und Zähnen sowie Muskel- und Gelenkschmerzen sind. Die klinische Symptomatik ist vom Erkrankungsalter abhängig und gestaltet sich sowohl interindividuell als auch intrafamiliär sehr variabel. Es werden sechs Unterformen der HPP abgegrenzt, wobei die Übergänge fließend sind. Sie reichen von der schweren perinatalen Form, die früher aufgrund fehlender Skelettmineralisierung meist tödlich war, bis hin zur adulten Form mit typischen Symptomen wie Frakturheilungsstörungen oder Stressfrakturen. Unspezifische Symptome wie Muskelschmerzen und -schwäche, Migräne oder Depressionen können ebenfalls Teil der HPP sein. Während schwere Formen mit einer Prävalenz zwischen 1/100.000 und 1/300.000 selten sind, kommen milde Formen der HPP deutlich häufiger vor. Perinatale und frühkindliche Formen sind meist autosomal-rezessiv vererbt, hingegen werden später auftretende Formen autosomal-rezessiv oder -dominant vererbt. Ursache der HPP ist eine reduzierte oder fehlende Aktivität der gewebeunspezifischen alkalischen Phosphatase (AP), welche durch das ALPL-Gen kodiert wird. Laborchemisch lassen sich im Serum eine alters- und geschlechtsspezifisch erniedrigte AP-Aktivität und eine konsekutive Erhöhung der AP-Substrate, z. B. des Pyridoxal-5-Phosphats (PLP), feststellen. Seit der Erstbeschreibung der Erkrankung 1948 haben sich die Diagnostik und Therapie der HPP dramatisch verbessert. Vor 4 Jahren ist eine Enzymersatztherapie mit Asfotase alfa (Strensiq®) für schwer betroffene HPP-Patienten mit Beginn der Erkrankung vor dem 18. Lebensjahr zugelassen worden. Dieser Artikel gibt einen Überblick über das breite klinische Spektrum der HPP, pathophysiologische Hintergründe, die laborchemische und molekulargenetische Diagnostik sowie gegenwärtige Therapieoptionen und deren Behandlungsindikationen.
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24
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Mao X, Liu S, Lin Y, Chen Z, Shao Y, Yu Q, Liu H, Lu Z, Sheng H, Lu X, Huang Y, Liu L, Zeng C. Two novel mutations in the ALPL gene of unrelated Chinese children with Hypophosphatasia: case reports and literature review. BMC Pediatr 2019; 19:456. [PMID: 31760938 PMCID: PMC6876108 DOI: 10.1186/s12887-019-1800-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 10/24/2019] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE Hypophosphatasia (HPP) is an inherited disorder of defective skeletal mineralization caused by mutations in the ALPL gene that encodes the Tissue Non-specific Alkaline Phosphatase (TNSALP). It is subdivided into six forms depending on the age of onset: perinatal lethal, prenatal benign, infantile, childhood, adult, and odonto HPP. Among these, infantile HPP is characterized by early onset and high frequency of lethal outcome. Few studies have reported the phenotype and genetic characteristics of HPP in Chinese children. CASE PRESENTATION Three forms of HPP were identified in four unrelated patients from four different Chinese families, including one lethal infantile (patient 1), two childhood (patient 2 and 3) and one odonto HPP (patient 4). Six variants in the ALPL gene were identified, including five missense mutations and one frameshift mutation. Of which, none were reported previously in the Chinese population, and two were novel (c.359G > C: p.G120A and c.1017dupG: p.H340AfsX3). Patient 1 carrying a novel homozygous (c.359G > C) mutation showed respiratory distress and pneumonia at first day of his life. He presented nearly negligible level of serum ALP activity, overall skeletal hypominaralization and died at 3 months old. Patient 2, 3 and 4 were compound heterozygotes with decreased serum ALP activity. Patient 2 and 3 presented premature loss of deciduous teeth, muscle weakness and bone pain, whereas patient 4 had early loss of deciduous teeth only. All four pedigrees exhibited autosomal recessive pattern of inheritance. CONCLUSIONS In this study, six mutations in the ALPL gene were found in four Chinese HPP patients, two of which were novel: c.359G > C in exon 5 and c.1017dupG in exon 10. Our results strongly indicated that the novel mutation c.359G > C might be disease-causing and associated with severe infantile form of HPP.
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Affiliation(s)
- Xiaojian Mao
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd, Guangzhou, 510623, China
| | - Sichi Liu
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd, Guangzhou, 510623, China
| | - Yunting Lin
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd, Guangzhou, 510623, China
| | - Zhen Chen
- Department of Radiology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - Yongxian Shao
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd, Guangzhou, 510623, China
| | - Qiaoli Yu
- Department of Dentistry, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - Haiying Liu
- Clinical Laboratory, Guangzhou Women and Children's Medical Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd., Guangzhou, 510623, China
| | - Zhikun Lu
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd, Guangzhou, 510623, China
| | - Huiyin Sheng
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd, Guangzhou, 510623, China
| | - Xinshuo Lu
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd, Guangzhou, 510623, China
| | - Yonglan Huang
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd, Guangzhou, 510623, China
| | - Li Liu
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd, Guangzhou, 510623, China.
| | - Chunhua Zeng
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, 9 Jinsui Rd, Guangzhou, 510623, China.
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Yokoi K, Nakajima Y, Shinkai Y, Sano Y, Imamura M, Akiyama T, Yoshikawa T, Ito T, Kurahashi H. Clinical and genetic aspects of mild hypophosphatasia in Japanese patients. Mol Genet Metab Rep 2019; 21:100515. [PMID: 31641588 PMCID: PMC6796780 DOI: 10.1016/j.ymgmr.2019.100515] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/05/2019] [Accepted: 09/02/2019] [Indexed: 11/29/2022] Open
Abstract
Background Hypophosphatasia (HPP) is a rare inborn error of metabolism that results from a dysfunctional tissue non-specific alkaline phosphatase enzyme (TNSALP). Although genotype-phenotype correlations have been described in HPP patients, only sparse information is currently available on the genetics of mild type HPP. Methods We investigated 5 Japanese patients from 3 families with mild HPP (patients 1 and 2 are siblings; patient 4 is a daughter of patient 5) who were referred to Fujita Health University due to the premature loss of deciduous teeth. Physical and dental examinations, and blood, urine and bone density tests were conducted. Genetic analysis of the ALPL gene was performed in all patients with their informed consent. Results After a detailed interview and examination, we found characteristic symptoms of HPP in some of the study cases. Mobile teeth or the loss of permanent teeth were observed in 2 patients, and 3 out of 5 patients had a history of asthma. The serum ALP levels of all patients were 30% below the lower limit of the age equivalent normal range. ALPL gene analysis revealed compound heterozygous mutations, including Ile395Val and Leu520Argfs in family 1, Val95Met and Gly491Arg in family 2, and a dominant missense mutation (Gly456Arg) in family 3. The 3D-modeling of human TNSALP revealed three mutations (Val95Met, Ile395Val and Gly456Arg) at the homodimer interface. Severe collisions between the side chains were predicted for the Gly456Arg variant. Discussion One of the characteristic findings of this present study was a high prevalence of coexisting asthma and a high level serum IgE level. These characteristics may account for the fragility of tracheal tissues and a predisposition to asthma in patients with mild HPP. The genotypes of the five mild HPP patients in our present study series included 1) compound heterozygous for severe and hypomorphic mutations, and 2) dominant-negative mutations. All of these mutations were at the homodimer interface, but only the dominant-negative mutation was predicted to cause a severe collision effect between the side chains. This may account for varying mechanisms leading to different effects on TNSALP function.
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Affiliation(s)
- Katsuyuki Yokoi
- Department of Pediatrics, Fujita Health University School of Medicine, Toyoake 470-1192, Japan.,Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake 470-1192, Japan
| | - Yoko Nakajima
- Department of Pediatrics, Fujita Health University School of Medicine, Toyoake 470-1192, Japan
| | - Yasuko Shinkai
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake 470-1192, Japan
| | - Yoshimi Sano
- Department of Plastic Surgery, Division of Pediatric Dentistry & Orthodontics, Fujita Health University of Medicine, Toyoake 470-1192, Japan
| | - Mototaka Imamura
- Department of Plastic Surgery, Division of Pediatric Dentistry & Orthodontics, Fujita Health University of Medicine, Toyoake 470-1192, Japan
| | - Tomoyuki Akiyama
- Department of Child Neurology, Okayama University Hospital, Okayama 700-8558, Japan
| | - Tetsushi Yoshikawa
- Department of Pediatrics, Fujita Health University School of Medicine, Toyoake 470-1192, Japan
| | - Tetsuya Ito
- Department of Pediatrics, Fujita Health University School of Medicine, Toyoake 470-1192, Japan
| | - Hiroki Kurahashi
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake 470-1192, Japan
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Okawa R, Kokomoto K, Kitaoka T, Kubota T, Watanabe A, Taketani T, Michigami T, Ozono K, Nakano K. Japanese nationwide survey of hypophosphatasia reveals prominent differences in genetic and dental findings between odonto and non-odonto types. PLoS One 2019; 14:e0222931. [PMID: 31600233 PMCID: PMC6786601 DOI: 10.1371/journal.pone.0222931] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 09/10/2019] [Indexed: 12/03/2022] Open
Abstract
Hypophosphatasia (HPP) is a rare and intractable metabolic bone disease caused by mutations in the ALPL gene. Here, we undertook a nationwide survey of HPP in Japan, specifically regarding the prominent genetic and dental manifestations of odonto (n = 16 cases) and other (termed “non-odonto”) (n = 36 cases) types. Mean serum alkaline phosphatase (ALP) values in odonto-type patients were significantly greater than those of non-odonto-type patients (P<0.05). Autosomal dominant and autosomal recessive inheritance patterns were detected, respectively, in 89% of odonto-type and 96% of non-odonto-type patients. The ALPL “c.1559delT” mutation, associated with extremely low ALP activity, was found in approximately 70% of cases. Regarding dental manifestations, all patients classified as odonto-type showed early exfoliation of the primary teeth significantly more frequently than patients classified as non-odonto-type (100% vs. 56%; P<0.05). Tooth hypomineralisation was detected in 42% of non-odonto-type patients, but not in any odonto-type patients (0%; P<0.05). Collectively, these results suggest that genetic and dental manifestations of patients with odonto-type and non-odonto-type HPP are significantly different, and these differences should be considered during clinical treatment of patients with HPP.
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Affiliation(s)
- Rena Okawa
- Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, Osaka, Japan
- * E-mail:
| | - Kazuma Kokomoto
- Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Taichi Kitaoka
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Takuo Kubota
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Atsushi Watanabe
- Division of Clinical Genetics, Kanazawa University Hospital, Ishikawa, Japan
| | - Takeshi Taketani
- Department of Pediatrics, Shimane University Faculty of Medicine, Shimane, Japan
| | - Toshimi Michigami
- Department of Pediatric Nephrology and Metabolism, and Department of Bone and Mineral Research, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka, Japan
| | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Kazuhiko Nakano
- Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, Osaka, Japan
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Uday S, Matsumura T, Saraff V, Saito S, Orimo H, Högler W. Tissue non-specific alkaline phosphatase activity and mineralization capacity of bi-allelic mutations from severe perinatal and asymptomatic hypophosphatasia phenotypes: Results from an in vitro mutagenesis model. Bone 2019; 127:9-16. [PMID: 31146036 DOI: 10.1016/j.bone.2019.05.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 05/24/2019] [Accepted: 05/25/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND Hypophosphatasia (HPP) is an inherited metabolic bone disease characterized by reduced mineralization due to mutations in the tissue non-specific alkaline phosphatase (ALPL) gene. HPP is clinically variable with extensive allelic heterogeneity in the ALPL gene. We report the findings of in vitro functional studies following site-directed mutagenesis in bi-allelic mutations causing extreme clinical phenotypes; severe perinatal and asymptomatic HPP. AIMS Elucidate genotype-phenotype correlation using in vitro functional studies and 3 dimensional (3D) ALP modelling. METHODS Clinical, biochemical and radiological features were recorded in two children with extreme HPP phenotypes: Subject 1 (S1): Perinatal HPP with compound heterozygous mutations (c.110T>C; c.532T>C); Subject 2 (S2): asymptomatic with homozygous missense mutation (c.715G>T). Plasmids created for mutants 1 c.110T>C (L37P), 2 c.532T>C (Y178H) and 3 c.715G>T (D239Y) using in vitro mutagenesis were transfected into human osteosarcoma (U2OS) cells and compared to wildtype (WT) and mock cDNA. ALP activity was measured using enzyme kinetics with p-nitrophenylphosphate. Mineral deposition was evaluated photometrically with Alizarin Red S staining after culture with mineralization medium. Western blot analysis was performed to identify the mature type protein expression (80 kDa). Mutations were located on a 3D ALP model. Co-transfection was performed to identify dominant negative effect of the mutants. RESULTS Phenotype: S1, had typical perinatal HPP phenotype at birth; extremely under-mineralized bones and pulmonary hypoplasia. S2, diagnosed incidentally by laboratory tests at 4 years, had normal growth, development, dentition and radiology. All S2's siblings (3 homozygous, 1 heterozygous) were asymptomatic. All subjects had typical biochemical features of HPP (low ALP, high serum pyridoxal-5'-phosphate), except the heterozygous sibling (normal ALP). Functional assay: Mutants 1 and 2 demonstrated negligible ALP activity and mineralization was 7.9% and 9.3% of WT, respectively. Mutant 3 demonstrated about 50% ALP activity and 15.5% mineralization of WT. On Western blot analysis, mutants 1 and 2 were detected as faint bands indicating reduced expression and mutant 3 was expressed as mature form protein with 50% of WT expression. Mutant 1 was located near the Glycosylphosphatidylinositol anchor, 2 at the core structure of the ALP protein and 3 at the periphery of the protein structure. Co-transfection did not reveal a dominant negative effect in any of the mutants. CONCLUSION Our findings expand the current knowledge of functional effect of individual mutations and the importance of their location in the ALP structure.
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Affiliation(s)
- Suma Uday
- Department of Endocrinology and Diabetes, Birmingham Women's and Children's Hospital, Birmingham, UK; Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Tomohiro Matsumura
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Vrinda Saraff
- Department of Endocrinology and Diabetes, Birmingham Women's and Children's Hospital, Birmingham, UK
| | - Shiho Saito
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Hideo Orimo
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Wolfgang Högler
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK; Department of Paediatrics and Adolescent Medicine, Johannes Kepler University, Linz, Austria.
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Hypophosphatasia and the importance of the general dental practitioner - a case series and discussion of upcoming treatments. Br Dent J 2019; 224:937-943. [PMID: 29999027 DOI: 10.1038/sj.bdj.2018.441] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/23/2018] [Indexed: 01/07/2023]
Abstract
Hypophosphatasia (HPP) is an inherited metabolic disorder that results in poorly mineralised bones and teeth. Clinical symptoms vary widely from mild dental anomalies to fatal fetal defects. The most common dental symptoms include exfoliation of the primary incisors before the age of three with little or no root resorption, large pulp chambers, alveolar bone loss and thin dentinal walls. There is generally minimal periodontal inflammation associated with the bony destruction and tooth loss. The general dental practitioner is usually the first clinician to spot signs of the milder forms of HPP. Patients diagnosed with dental symptoms in childhood can go on to develop significant morbidity in middle age with chronic bone pain and stress fractures of the long bones. The primary dental care clinician is the key to early diagnosis of such cases, whether they present in childhood or adulthood. Emerging enzyme replacement therapy has considerably changed the landscape of the disease, resulting in astonishing improvements in bone mineralisation and a significant reduction in mortality and morbidity. It is increasingly likely that primary and secondary care clinicians will treat patients with the severe forms of HPP, who would previously not have survived infancy.
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Ishiguro T, Sugiyama Y, Ueda K, Muramatsu Y, Tsuda H, Kotani T, Michigami T, Tachikawa K, Akiyama T, Hayakawa M. Findings of amplitude-integrated electroencephalogram recordings and serum vitamin B6 metabolites in perinatal lethal hypophosphatasia during enzyme replacement therapy. Brain Dev 2019; 41:721-725. [PMID: 31000369 DOI: 10.1016/j.braindev.2019.03.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 03/17/2019] [Accepted: 03/29/2019] [Indexed: 11/24/2022]
Abstract
Hypophosphatasia (HPP) is a rare disorder caused by low serum tissue non-specific alkaline phosphatase (ALP) activity due to hypomorphic mutations in the ALPL gene. HPP is characterized by defective bone mineralization. It frequently accompanies pyridoxine-responsive seizures. Because alkaline phosphatase change pyridoxal 5' phosphate (PLP) into pyridoxal (PL), which can cross the blood brain barrier and regulates inhibitory neurotransmitter gamma-aminobutyric acid. The female patient was born at a gestational age of 37 weeks 2 days. She presented severe respiratory disorder due to extreme thoracic hypoplasia. With the extremely low serum ALP value (14 IU/L), she was clinically diagnosed as HPP. The diagnosis was confirmed with genetic testing. On day1, the subclinical seizures were detected by aEEG. Together with enzyme replacement therapy by asfotase alfa, pyridoxine hydrochloride was administered, then the seizures were rapidly controlled. While confirming that there was no seizure by aEEG monitoring, pyridoxine hydrochloride was gradually discontinued after 1 month. Before administration of pyridoxine hydrochloride, PL was extremely low (4.7 nM) and PLP was increased (1083 nM). After the withdrawal, PL was increased to 84.9 nM only by enzyme replacement. Monitoring with aEEG enabled early intervention for pyridoxine responsive seizures. Confirming increased serum PL concentration is a prudent step in determining when to reduce or discontinue pyridoxine hydrochloride during enzyme replacement therapy.
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Affiliation(s)
- Tomonori Ishiguro
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yuichiro Sugiyama
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan; Division of Neonatology, Center for Maternal-Neonatal Care, Nagoya University Hospital, Nagoya, Japan.
| | - Kazuto Ueda
- Division of Neonatology, Center for Maternal-Neonatal Care, Nagoya University Hospital, Nagoya, Japan
| | - Yukako Muramatsu
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroyuki Tsuda
- Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tomomi Kotani
- Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Toshimi Michigami
- Department of Bone and Mineral Research, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Kanako Tachikawa
- Department of Bone and Mineral Research, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Tomoyuki Akiyama
- Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Masahiro Hayakawa
- Division of Neonatology, Center for Maternal-Neonatal Care, Nagoya University Hospital, Nagoya, Japan
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Rush ET, Moseley S, Petryk A. Burden of disease in pediatric patients with hypophosphatasia: results from the HPP Impact Patient Survey and the HPP Outcomes Study Telephone interview. Orphanet J Rare Dis 2019; 14:201. [PMID: 31419999 PMCID: PMC6698035 DOI: 10.1186/s13023-019-1167-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/26/2019] [Indexed: 11/10/2022] Open
Abstract
Background Hypophosphatasia (HPP) is a rare, inherited, metabolic bone disease caused by deficient tissue-non-specific isoenzyme of alkaline phosphatase activity that manifests as a broad range of signs/symptoms, including bone mineralization defects and systemic complications. The burden of disease is poorly characterized, particularly in children. This study aimed to characterize the patient-reported burden of disease among children with HPP using two survey instruments: the HPP Impact Patient Survey (HIPS) and the HPP Outcomes Study Telephone interview (HOST). Methods Between September 2009 and June 2011, pediatric patients (aged younger than 18 years) with HPP were recruited to participate in the study via patient advocacy groups or their medical provider. Survey questions were used to capture information on patient demographics, HPP-related medical history, mobility, and health-related quality of life (HRQoL; using the 10-item Short-Form Health Survey for Children [SF-10], HIPS only). Results Common clinical features of the 59 pediatric survey respondents (mean [standard deviation] age: 7.6 [5.1] years; 51% male) included pain (86% of patients), muscle weakness (71%), difficulty gaining weight (64%), and delayed walking (59%). Fracture was reported by 36% of patients; multiple fractures were also reported (15% of patients). Use of assistive devices for mobility was frequent among the study population (51%). In response to the SF-10, patients reported a substantial impact of HPP on their HRQoL; physical function was the most severely impaired component relative to normative data. Of patients responding to the HOST, two-thirds experienced worsening of at least one of their HPP-related signs/symptoms over a 5-year period. Conclusions In pediatric patients, HPP is associated with a high burden of disease and a substantial negative impact on HRQoL. The burden of HPP may increase and HRQoL reduce further over time as signs/symptoms that affect HRQoL worsen or new signs/symptoms manifest. Electronic supplementary material The online version of this article (10.1186/s13023-019-1167-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Eric T Rush
- Children's Mercy Hospital, University of Missouri - Kansas City School of Medicine, Kansas City, MO, USA.
| | | | - Anna Petryk
- Alexion Pharmaceuticals, Inc., New Haven, CT, USA
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Ishijima Y, Iizuka T, Kagami K, Masumoto S, Nakade K, Mitani Y, Niida Y, Watanabe A, Yamazaki R, Ono M, Fujiwara H. Prenatal diagnosis facilitated prompt enzyme replacement therapy for prenatal benign hypophosphatasia. J OBSTET GYNAECOL 2019; 40:132-134. [PMID: 31335231 DOI: 10.1080/01443615.2019.1606177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Yuka Ishijima
- Department of Obstetrics and Gynaecology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Takashi Iizuka
- Department of Obstetrics and Gynaecology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Kyosuke Kagami
- Department of Obstetrics and Gynaecology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Sakiko Masumoto
- Department of Obstetrics and Gynaecology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Kyohei Nakade
- Department of Obstetrics and Gynaecology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Yusuke Mitani
- Department of Pediatrics, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Yo Niida
- Center for Clinical Genomics, Kanazawa Medical University Hospital, Uchinada, Japan
| | - Atsushi Watanabe
- Clinical Genetics, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Rena Yamazaki
- Department of Obstetrics and Gynaecology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Masanori Ono
- Department of Obstetrics and Gynaecology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Hiroshi Fujiwara
- Department of Obstetrics and Gynaecology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
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Whyte MP, Leung E, Wilcox WR, Liese J, Argente J, Martos-Moreno GÁ, Reeves A, Fujita KP, Moseley S, Hofmann C. Natural History of Perinatal and Infantile Hypophosphatasia: A Retrospective Study. J Pediatr 2019; 209:116-124.e4. [PMID: 30979546 DOI: 10.1016/j.jpeds.2019.01.049] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 01/16/2019] [Accepted: 01/29/2019] [Indexed: 01/13/2023]
Abstract
OBJECTIVE To report clinical characteristics and medical history data obtained retrospectively for a large cohort of pediatric patients with perinatal and infantile hypophosphatasia. STUDY DESIGN Medical records from academic medical centers known to diagnose and/or treat hypophosphatasia were reviewed. Patients born between 1970 and 2011 with hypophosphatasia and any of the following signs/symptoms at age <6 months were eligible: vitamin B6-dependent seizures, respiratory compromise, or rachitic chest deformity (NCT01419028). Patient demographics and characteristics, respiratory support requirements, invasive ventilator-free survival, and further complications of hypophosphatasia were followed for up to the first 5 years of life. RESULTS Forty-eight patients represented 12 study sites in 7 countries; 13 patients were alive, and 35 were dead (including 1 stillborn). Chest deformity, respiratory distress, respiratory failure (as conditioned by the eligibility criteria), failure to thrive, and elevated calcium levels were present in >70% of patients between birth and age 5 years. Vitamin B6-dependent seizures and respiratory distress and failure were associated significantly (P < .05) with the risk of early death. Serum alkaline phosphatase activity in all 41 patients tested (mean [SD]: 18.1 [15.4] U/L) was below the mean lower limit of normal of the reference ranges of the various laboratories (88.2 U/L). Among the 45 patients with relevant data, 29 had received respiratory support, of whom 26 had died at the time of data collection. The likelihood of invasive ventilator-free survival for this cohort decreased to 63% at 3 months, 54% at 6 months, 31% at 12 months, and 25% at 5 years. CONCLUSIONS Patients with perinatal or infantile hypophosphatasia and vitamin B6-dependent seizures, with or without significant respiratory distress or chest deformities, have high morbidity and mortality in the first 5 years of life. TRIAL REGISTRATION ClinicalTrials.gov: NCT01419028.
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Affiliation(s)
- Michael P Whyte
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospital for Children, St Louis, MO; Division of Bone and Mineral Diseases, Department of Internal Medicine, Washington University School of Medicine at Barnes-Jewish Hospital, St Louis, MO.
| | - Edward Leung
- Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, Manitoba, Canada
| | - William R Wilcox
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA
| | - Johannes Liese
- University Children's Hospital, University of Würzburg, Würzburg, Germany
| | - Jesús Argente
- Hospital Infantil Universitario Niño Jesús, Universidad Autónoma de Madrid, CIBERobn, ISCIII, IMDEA Food Institute, CEIUAM+CSIC, Madrid, Spain
| | - Gabriel Á Martos-Moreno
- Hospital Infantil Universitario Niño Jesús, Universidad Autónoma de Madrid, CIBERobn, ISCIII, IMDEA Food Institute, CEIUAM+CSIC, Madrid, Spain
| | - Amy Reeves
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospital for Children, St Louis, MO
| | - Kenji P Fujita
- Clinical Research, Alexion Pharmaceuticals, Inc, Boston, MA
| | - Scott Moseley
- Biostatistics, Alexion Pharmaceuticals, Inc, Boston, MA
| | - Christine Hofmann
- University Children's Hospital, University of Würzburg, Würzburg, Germany
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Nakano C, Kitabatake Y, Takeyari S, Ohata Y, Kubota T, Taketani K, Kogo M, Ozono K. Genetic correction of induced pluripotent stem cells mediated by transcription activator-like effector nucleases targeting ALPL recovers enzyme activity and calcification in vitro. Mol Genet Metab 2019; 127:158-165. [PMID: 31178256 DOI: 10.1016/j.ymgme.2019.05.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 05/25/2019] [Accepted: 05/25/2019] [Indexed: 01/22/2023]
Abstract
Hypophosphatasia (HPP) is an inheritable disease affecting both skeletal systems and extra-skeletal organs due to mutations of the gene ALPL, which encodes tissue-nonspecific alkaline phosphatase. Recently, an enzyme replacement therapy using asfotase alfa was developed to ameliorate the complications of HPP. However, it requires frequent injections and is expensive to maintain. As an alternative, cell and gene therapy using human induced pluripotent stem cells (iPSCs) after precise correction of the mutation is feasible due to advances in genome-editing technology. In the study, we examined the alkaline phosphatase (ALP) activity and calcification in vitro of two childhood HPP patient-derived iPSCs after the correction of the c.1559delT mutation, which is the most frequent mutation in Japanese patients with HPP, using transcription activator-like effector nucleases (TALENs). The gene correction targeting vector was designed for site-directed mutagenesis using TALEN. After selection with antibiotics, some clones with the selection cassette were obtained. Gene correction was confirmed by Sanger sequencing. The mutation was corrected in one allele of ALPL in homozygous patients and compound heterozygous patients. The correction of ALPL did not result in an increase in ALP when the selection cassette remained. Conversely, iPSCs exhibited ALP activity after the elimination of the cassette using Cre/LoxP. The quantitative analysis showed the half ALP activity in corrected iPSCs of that of control iPSCs, corresponding to heterozygous correction of the mutation. In addition, osteoblasts differentiated from the corrected iPSCs exhibited high ALP activity and some calcification in vitro. Moreover, the osteoblast-like phenotype was confirmed by increased expression of osteoblast-specific genes such as COL1A1 and osteocalcin. These results suggest that gene correction in iPSCs may be a candidate treatment for HPP patients.
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Affiliation(s)
- Chiho Nakano
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan; Unit of Dentistry, Osaka University Hospital, Osaka, Japan
| | - Yasuji Kitabatake
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Shinji Takeyari
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yasuhisa Ohata
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Takuo Kubota
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Ken Taketani
- Department of Pediatrics, Shimane University, Osaka, Japan
| | - Mikihiko Kogo
- Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan.
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Fukushima K, Kawai-Kowase K, Yonemoto Y, Fujiwara M, Sato H, Sato M, Kubota T, Ozono K, Tamura J. Adult hypophosphatasia with compound heterozygous p.Phe327Leu missense and c.1559delT frameshift mutations in tissue-nonspecific alkaline phosphatase gene: a case report. J Med Case Rep 2019; 13:101. [PMID: 31014398 PMCID: PMC6480864 DOI: 10.1186/s13256-019-2045-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 03/08/2019] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Hypophosphatasia is an inherited bone disease characterized by low alkaline phosphatase activity encoded by ALPL. Clinically, hypophosphatasia can be categorized as perinatal, infantile, childhood, and adult forms, as well as odonto-hypophosphatasia, according to the age at first sign or dental manifestations. Adult hypophosphatasia typically presents in middle-aged patients who appear to be in good health in early adulthood and manifests as painful feet caused by recurrent, slow-healing stress fractures of the lower limb. Because the symptoms of adult hypophosphatasia vary and are common, many patients with hypophosphatasia might be not diagnosed accurately and thus may receive inappropriate treatment. CASE PRESENTATION We report a case of a 35-year-old Japanese woman with low serum alkaline phosphatase detected at a routine medical checkup. She had mild muscle/bone pain but no history of rickets, fractures, or dental problems. Measurement of bone mineral density of the lumbar spine and the femoral neck revealed osteopenia below the expected range for age in a young adult. Abdominal ultrasonography revealed numerous microcalcifications in both kidneys. Analysis of amino acids in urine revealed that phosphoethanolamine was elevated. Low serum alkaline phosphatase activity, elevation of phosphoethanolamine, and low bone mineral density supported the diagnosis of hypophosphatasia. ALPL mutation analysis revealed two mutations: p.Phe327Leu and c.1559delT. These genetic abnormalities were previously reported in perinatal, infantile, and childhood but not adult hypophosphatasia. On the basis of the clinical presentation, laboratory and imaging findings, and genetic analyses, the patient was definitively diagnosed with adult hypophosphatasia. To the best of our knowledge, this is the first case report of adult hypophosphatasia with the compound heterozygous mutations p.Phe327Leu and c.1559delT. CONCLUSIONS Although the risk of bone fracture was high in this case, treatment approaches differ between osteoporosis and hypophosphatasia. Because adult hypophosphatasia diagnosis is often difficult because of their varied symptoms, hypophosphatasia should be considered in the differential diagnosis of low serum alkaline phosphatase. Early diagnosis is important so that appropriate treatment can be initiated.
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Affiliation(s)
- Kazunori Fukushima
- Department of Emergency Medicine, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Keiko Kawai-Kowase
- Department of General Medicine, Gunma University Graduate School of Medicine, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8511, Japan.
| | - Yukio Yonemoto
- Department of Orthopedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Makoto Fujiwara
- Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Hiroko Sato
- Department of General Medicine, Gunma University Graduate School of Medicine, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8511, Japan
| | - Mahito Sato
- Department of General Medicine, Gunma University Graduate School of Medicine, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8511, Japan
| | - Takuo Kubota
- Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Junich Tamura
- Department of General Medicine, Gunma University Graduate School of Medicine, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8511, Japan
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Kishnani PS, Rockman-Greenberg C, Rauch F, Bhatti MT, Moseley S, Denker AE, Watsky E, Whyte MP. Five-year efficacy and safety of asfotase alfa therapy for adults and adolescents with hypophosphatasia. Bone 2019; 121:149-162. [PMID: 30576866 DOI: 10.1016/j.bone.2018.12.011] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 12/11/2018] [Accepted: 12/13/2018] [Indexed: 12/12/2022]
Abstract
Hypophosphatasia (HPP) features low tissue-nonspecific alkaline phosphatase (TNSALP) isoenzyme activity resulting in extracellular accumulation of its substrates including pyridoxal 5'-phosphate (PLP), the principal circulating form of vitamin B6, and inorganic pyrophosphate (PPi), a potent inhibitor of mineralization. Asfotase alfa is an enzyme replacement therapy developed to treat HPP. This multinational, randomized, open-label study (NCT01163149; EudraCT 2010-019850-42) evaluated the efficacy and safety of asfotase alfa in adults and adolescents 13-66 years of age with HPP. The study comprised a 6-month primary treatment period and a 4.5-year extension phase. In the primary treatment period, 19 patients were randomized to receive asfotase alfa 0.3 mg/kg/d subcutaneously (SC; n = 7), asfotase alfa 0.5 mg/kg/d SC (n = 6), or no treatment (control; n = 6) for 6 months. In the extension phase, patients received asfotase alfa (0.5 mg/kg/d for 6 mo-1 y, then 1 mg/kg/d 6 d/wk). During the primary treatment period, changes from Baseline to Month 6 in plasma PLP and PPi concentrations (coprimary efficacy measure) were greater in the combined asfotase alfa group compared with the control group, reaching statistical significance for PLP (P = 0.0285) but not for PPi (P = 0.0715). However, for the total cohort, the within subject changes in both PLP and PPi after 6 months and over 5 years of treatment with asfotase alfa were significant (P < 0.05). Secondary efficacy measures included transiliac crest histomorphometry, dual-energy X-ray absorptiometry (DXA), and the 6-Minute Walk Test (6MWT). A significant decrease from Baseline in mineralization lag time was observed in the combined asfotase alfa group at Year 1. There were no significant differences between treated and control patients in DXA mean bone mineral density results at 6 months; Z-scores and T-scores were within the expected range for age at Baseline and remained so over 5 years of treatment. On the 6MWT, median (min, max) distance walked increased from 355 (10, 620; n = 19) meters before treatment to 450 (280, 707; n = 13) meters at 5 years (P < 0.05). Results for the exploratory outcome measures suggested improvements in gross motor function, muscle strength, and patient-reported functional disability over 5 years of treatment. There were no deaths during this study. Asfotase alfa was generally well tolerated; the most common adverse events were mild to moderate injection site reactions. This study suggests that in adults and adolescents with pediatric-onset HPP, treatment with asfotase alfa is associated with normalization of circulating TNSALP substrate levels and improved functional abilities.
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Affiliation(s)
| | - Cheryl Rockman-Greenberg
- The University of Manitoba, Rady Faculty of Health Sciences, Max Rady College of Medicine, Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada.
| | - Frank Rauch
- McGill University, Shriners Hospital for Children, Montreal, Quebec, Canada.
| | - M Tariq Bhatti
- Duke Eye Center, Duke University Medical Center, Durham, NC, USA
| | | | | | - Eric Watsky
- Alexion Pharmaceuticals, Inc., Boston, MA, USA.
| | - Michael P Whyte
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospital for Children, St. Louis, MO, USA; Division of Bone and Mineral Diseases, Department of Internal Medicine, Washington University School of Medicine at Barnes-Jewish Hospital, St. Louis, MO, USA.
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Luo E, Liu H, Zhao Q, Shi B, Chen Q. Dental-craniofacial manifestation and treatment of rare diseases. Int J Oral Sci 2019; 11:9. [PMID: 30783081 PMCID: PMC6381182 DOI: 10.1038/s41368-018-0041-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 10/22/2018] [Accepted: 10/28/2018] [Indexed: 02/05/2023] Open
Abstract
Rare diseases are usually genetic, chronic and incurable disorders with a relatively low incidence. Developments in the diagnosis and management of rare diseases have been relatively slow due to a lack of sufficient profit motivation and market to attract research by companies. However, due to the attention of government and society as well as economic development, rare diseases have been gradually become an increasing concern. As several dental-craniofacial manifestations are associated with rare diseases, we summarize them in this study to help dentists and oral maxillofacial surgeons provide an early diagnosis and subsequent management for patients with these rare diseases.
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Affiliation(s)
- En Luo
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Hanghang Liu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qiucheng Zhao
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Bing Shi
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
| | - Qianming Chen
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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Högler W, Langman C, Gomes da Silva H, Fang S, Linglart A, Ozono K, Petryk A, Rockman-Greenberg C, Seefried L, Kishnani PS. Diagnostic delay is common among patients with hypophosphatasia: initial findings from a longitudinal, prospective, global registry. BMC Musculoskelet Disord 2019; 20:80. [PMID: 30764793 PMCID: PMC6376686 DOI: 10.1186/s12891-019-2420-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 01/16/2019] [Indexed: 12/04/2022] Open
Abstract
Background Hypophosphatasia (HPP) is a rare, systemic disease caused by mutation(s) within the ALPL gene encoding tissue-nonspecific alkaline phosphatase (ALP). HPP has a heterogeneous presentation, which coupled with its rarity, often leads to missed/delayed diagnosis and an incomplete understanding of its natural history. To better understand the epidemiology and clinical course of HPP, including timing of diagnosis after first reported manifestation, we present baseline data for patients enrolled in the Global HPP Registry. Methods Data were analyzed from patients with an HPP diagnosis confirmed by low serum ALP activity and/or an ALPL pathogenic variant, regardless of prior or current treatment, according to age at enrollment (children: < 18 y; adult: ≥18 y). All analyses were descriptive. Results Of 269 patients from 11 countries enrolled January 2015–September 2017, 121 (45.0%) were children and 148 (55.0%) were adults. The majority of children and adults were female (61.2 and 73.0%, respectively) and white (57.7 and 90.0%, respectively). Children had a median (min, max) age at earliest reported HPP manifestation of 7.2 months (− 2.3 mo, 16.0 y), which was > 12 months before diagnosis at age 20.4 months (− 0.2 mo, 16.0 y). In adults, the earliest reported manifestation occurred at a median (min, max) age of 37.6 years (0.2 y, 75.2 y), which preceded age at diagnosis (47.5 years [0.2 y, 75.2 y]) by ~ 10 years. Premature loss of deciduous teeth (48.2%, age ≥ 6 mo), bone deformity (32.5%), and failure to thrive (26.7%) were most commonly reported in the HPP-related disease history of children. Pain (74.5%), orthopedic procedures and therapies (44.6%), and recurrent and poorly healing fractures (36.5%) were most commonly reported in the HPP-related disease history of adults. Conclusions The Global HPP Registry represents the largest observational study of patients with HPP, capturing real world data. This analysis shows that diagnostic delay is common, reflecting limited awareness of HPP, and that HPP is associated with systemic manifestations across all ages. Many patients diagnosed in adulthood had HPP manifestations in childhood, highlighting the importance of taking thorough medical histories to ensure timely diagnosis. Trial registration Clinicaltrials.gov: NCT02306720, December 2014; ENCePP.eu: EUPAS13526, May 2016 (retrospectively registered).
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Affiliation(s)
- Wolfgang Högler
- Department of Pediatrics and Adolescent Medicine, Johannes Kepler University Linz, Linz, Austria
| | - Craig Langman
- Feinberg School of Medicine, Northwestern University and Lurie Children's Hospital, Chicago, IL, USA
| | | | - Shona Fang
- Alexion Pharmaceuticals, Inc., Boston, MA, USA
| | - Agnès Linglart
- APHP, Bicêtre Paris-Sud, University Paris Sud, Paris-Saclay, Le Kremlin Bicêtre, Paris, France
| | - Keiichi Ozono
- Department of Pediatrics, Osaka University, Graduate School of Medicine, Suita, Osaka, Japan
| | - Anna Petryk
- Alexion Pharmaceuticals, Inc., Boston, MA, USA
| | - Cheryl Rockman-Greenberg
- Rady Faculty of Health Sciences, Max Rady College of Medicine, and Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Lothar Seefried
- Orthopaedic Clinic, König-Ludwig-Haus, University of Würzburg, Würzburg, Germany
| | - Priya S Kishnani
- Department of Pediatrics, Duke University Medical Center, 2301 Erwin Rd, Durham, NC, 27710, USA.
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A homozygous missense variant in the alkaline phosphatase gene ALPL is associated with a severe form of canine hypophosphatasia. Sci Rep 2019; 9:973. [PMID: 30700765 PMCID: PMC6353930 DOI: 10.1038/s41598-018-37801-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 12/13/2018] [Indexed: 12/25/2022] Open
Abstract
Inherited skeletal disorders affect both humans and animals. In the current study, we have performed series of clinical, pathological and genetic examinations to characterize a previously unreported skeletal disease in the Karelian Bear Dog (KBD) breed. The disease was recognized in seven KBD puppies with a variable presentation of skeletal hypomineralization, growth retardation, seizures and movement difficulties. Exome sequencing of one affected dog revealed a homozygous missense variant (c.1301T > G; p.V434G) in the tissue non-specific alkaline phosphatase gene, ALPL. The identified recessive variant showed full segregation with the disease in a cohort of 509 KBDs with a carrier frequency of 0.17 and was absent from 303 dogs from control breeds. In humans, recessive and dominant ALPL mutations cause hypophosphatasia (HPP), a metabolic bone disease with highly heterogeneous clinical manifestations, ranging from lethal perinatal hypomineralization to a relatively mild dental disease. Our study reports the first naturally occurring HPP in animals, resembling the human infantile form. The canine HPP model may serve as a preclinical model while a genetic test will assist in breeding programs.
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Taillandier A, Domingues C, Dufour A, Debiais F, Guggenbuhl P, Roux C, Cormier C, Cortet B, Porquet-Bordes V, Coury F, Geneviève D, Chiesa J, Colin T, Fletcher E, Guichet A, Javier RM, Laroche M, Laurent M, Lausch E, LeHeup B, Lukas C, Schwabe G, van der Burgt I, Muti C, Simon-Bouy B, Mornet E. Genetic analysis of adults heterozygous for ALPL mutations. J Bone Miner Metab 2018; 36:723-733. [PMID: 29236161 DOI: 10.1007/s00774-017-0888-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 11/11/2017] [Indexed: 12/11/2022]
Abstract
Hypophosphatasia (HPP) is a rare inherited metabolic bone disease due to a deficiency of the tissue nonspecific alkaline phosphatase isoenzyme (TNSALP) encoded by the ALPL gene. Patients have consistently low serum alkaline phosphatase (AP), so that this parameter is a good hallmark of the disease. Adult HPP is heterogeneous, and some patients present only mild nonpathognomonic symptoms which are also common in the general population such as joint pain, osteomalacia and osteopenia, chondrocalcinosis, arthropathy and musculoskeletal pain. Adult HPP may be recessively or dominantly inherited; the latter case is assumed to be due to the dominant negative effect (DNE) of missense mutations derived from the functional homodimeric structure of TNSALP. However, there is no biological argument excluding the possibility of other causes of dominant HPP. Rheumatologists and endocrinologists are increasingly solicited for patients with low AP and nonpathognomonic symptoms of HPP. Many of these patients are heterozygous for an ALPL mutation and a challenging question is to determine if these symptoms, which are also common in the general population, are attributable to their heterozygous ALPL mutation or not. In an attempt to address this question, we reviewed a cohort of 61 adult patients heterozygous for an ALPL mutation. Mutations were distinguished according to their statistical likelihood to show a DNE. One-half of the patients carried mutations predicted with no DNE and were slightly less severely affected by the age of onset, serum AP activity and history of fractures. We hypothesized that these mutations result in another mechanism of dominance or are recessive alleles. To identify other genetic factors that could trigger the disease phenotype in heterozygotes for potential recessive mutations, we examined the next-generation sequencing results of 32 of these patients for a panel of 12 genes involved in the differential diagnosis of HPP or candidate modifier genes of HPP. The heterozygous genotype G/C of the COL1A2 coding SNP rs42524 c.1645C > G (p.Pro549Ala) was associated with the severity of the phenotype in patients carrying mutations with a DNE whereas the homozygous genotype G/G was over-represented in patients carrying mutations without a DNE, suggesting a possible role of this variant in the disease phenotype. These preliminary results support COL1A2 as a modifier gene of HPP and suggest that a significant proportion of adult heterozygotes for ALPL mutations may have unspecific symptoms not attributable to their heterozygosity.
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Affiliation(s)
- Agnès Taillandier
- Unité de Génétique Constitutionnelle, Service de Biologie, Centre Hospitalier de Versailles, 177 rue de Versailles, 78150, Le Chesnay, France
| | - Christelle Domingues
- Unité de Génétique Constitutionnelle, Service de Biologie, Centre Hospitalier de Versailles, 177 rue de Versailles, 78150, Le Chesnay, France
| | - Annika Dufour
- Unité de Génétique Constitutionnelle, Service de Biologie, Centre Hospitalier de Versailles, 177 rue de Versailles, 78150, Le Chesnay, France
| | - Françoise Debiais
- Service de Rhumatologie, CHU de Poitiers, 86021, Poitiers cedex, France
| | - Pascal Guggenbuhl
- Service de Rhumatologie, hôpital Sud, CHU de Rennes, 16, boulevard de Bulgarie, BP90347, 35203, Rennes cedex 2, France
| | | | | | | | - Valérie Porquet-Bordes
- Endocrinologie, Maladies Osseuses, Génétique et Gynécologie Médicale, Hôpital des Enfants, CHU de Toulouse, Toulouse Cedex 9, France
| | - Fabienne Coury
- Service de Rhumatologie, CHU Lyon, Centre Hospitalier Lyon-Sud, Pierre Bénite, France
| | - David Geneviève
- Service de Génétique Clinique, Département de Génétique Médicale, maladies rares et médecine personnalisée, CHU Montpellier, université Montpellier, unité Inserm U1183, Montpellier, France
| | - Jean Chiesa
- Department of Genetics, University Hospital, Nîmes, France
| | - Thierry Colin
- Service de Rhumatologie, CH Public du Cotentin, Cherbourg, France
| | - Elaine Fletcher
- Clinical Genetics, Molecular Medicine Center, Western General Hospital, Edinburgh, UK
| | - Agnès Guichet
- Département Biochimie et génétique, CHU d'Angers, Angers, France
| | | | - Michel Laroche
- Service de Rhumatologie, Hôpital Pierre-Paul Riquet, Toulouse, France
| | - Michael Laurent
- Center for Metabolic Bone Diseases, University Hospitals Leuven, Leuven, Belgium
| | - Ekkehart Lausch
- Universitätsklinikum Freiburg, Zentrum für Kinder- und Jugendmedizin, Freiburg, Germany
| | - Bruno LeHeup
- Médecine infantile 3, CHU Nancy, Vandoeuvre, France
| | - Cédric Lukas
- Département de Rhumatologie, CHRU Montpellier, Montpellier, France
| | - Georg Schwabe
- Otto-Heubner-Centrum für Kinder und Jugendmedizin Allgemeine Päediatrie Charité, Campus Virchow Klinikum Augustenburger Platz 1, Berlin, Germany
| | | | - Christine Muti
- Unité de Génétique Constitutionnelle, Service de Biologie, Centre Hospitalier de Versailles, 177 rue de Versailles, 78150, Le Chesnay, France
| | - Brigitte Simon-Bouy
- Unité de Génétique Constitutionnelle, Service de Biologie, Centre Hospitalier de Versailles, 177 rue de Versailles, 78150, Le Chesnay, France
| | - Etienne Mornet
- Unité de Génétique Constitutionnelle, Service de Biologie, Centre Hospitalier de Versailles, 177 rue de Versailles, 78150, Le Chesnay, France.
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Castells L, Cassanello P, Muñiz F, de Castro MJ, Couce ML. Neonatal lethal hypophosphatasia: A case report and review of literature. Medicine (Baltimore) 2018; 97:e13269. [PMID: 30508915 PMCID: PMC6283130 DOI: 10.1097/md.0000000000013269] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
RATIONALE Hypophosphatasia (HPP) is a very rare metabolic bone disease caused by loss-of-function mutations in the ALPL gene encoding the tissue nonspecific alkaline phosphatase. The severe neonatal form is considered lethal but insights into manifestations of the disease can help to increase our knowledge of the natural history for an early initiation of treatment and improvement of survival. PATIENT CONCERNS We report the case of a newborn in which his fetal imaging showed findings of skeletal dysplasia disorder, considering initially achondroplasia as a potential diagnosis. DIAGNOSIS A definitive diagnosis compatible with perinatal lethal HPP was established in the 1st days due to the presentation at birth with thoracic and pulmonary hypoplasia, bone hypomineralization, and undetectable alkaline phosphatase. The genetic analysis identified a new heterozygous c.413G>C mutation and another 1 c.473-2G>C previously described in the ALPL gene. OUTCOMES The patient died on the 4th day by clinical course complicated without having started enzyme replacement therapy (ERT). Retrospectively, previous analyzes of the parents already showed both a decreased alkaline phosphatase. LESSONS This report highlights the importance of prenatal differential diagnosis of bone dysplasia with the key biochemical marker of alkaline phosphatase in the parents. Substitutive ERT administered very soon after birth, seems to change the prognosis in these patients with neonatal HPP.
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Affiliation(s)
- Laura Castells
- Neonatal and Perinatal Unit, Hospital Universitari General de Catalunya Quirónsalud, Sant Cugat del Vallès, Barcelona
| | - Pía Cassanello
- Neonatal and Perinatal Unit, Hospital Universitari General de Catalunya Quirónsalud, Sant Cugat del Vallès, Barcelona
| | - Felix Muñiz
- Neonatal and Perinatal Unit, Hospital Universitari General de Catalunya Quirónsalud, Sant Cugat del Vallès, Barcelona
| | - María-José de Castro
- Neonatal Service, Metabolic Unit, Department of Pediatrics, Santiago de Compostela University Hospital, IDIS (Health Research Institute of Santiago de Compostela), Ciberer, Spain
| | - María L. Couce
- Neonatal Service, Metabolic Unit, Department of Pediatrics, Santiago de Compostela University Hospital, IDIS (Health Research Institute of Santiago de Compostela), Ciberer, Spain
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Abstract
Hypophosphatasia (HPP) is a rare inherited disorder primarily affecting bone and dental mineralization. Although there is a continuum in the severity of the disease, clinical forms may be arbitrarily distinguished on the basis of age at onset and the presence or absence of bone symptoms: perinatal, infantile, juvenile, adult, prenatal benign, and odontological. Severe forms (perinatal and infantile) are autosomally recessively inherited while less severe forms may be autosomally recessively or dominantly inherited. Genetic counseling is complicated by the coexistence of the two modes of inheritance, the incomplete penetrance of the dominant forms, the markedly variable expression of the disease, including intra-familial expression, and the existence of a benign prenatal form that may sometimes be difficult to distinguish from the severe prenatal form. The disease is due to loss-of-function mutations in the Alkaline Phosphatase-Liver (ALPL) gene encoding the tissue nonspecific alkaline phosphatase (TNSALP). The great variety of missence mutations and the dominant negative effect of some mutations largely explain the clinical heterogeneity. Directed mutagenesis studies allowed further elucidation of the cellular pathophysiology of HPP, classification of the alleles in terms of their severity and dominant negative effect, and molecular explanations of the dominant inheritance mode. Genetics significantly contributed to show that there are in fact two HPPs, rare, severe and recessive HPP, and mild recessive or mild dominant HPP, which is markedly more frequent and probably under-diagnosed. The prevalence of the severe forms of HPP has been estimated to be 1/300,000 in France and Northern Europe while the prevalence of the moderate forms of HPP may reach 1/6,370.
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Affiliation(s)
- E Mornet
- Service de biologie, unité de génétique constitutionnelle, centre hospitalier de Versailles, Le Chesnay, France.
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Rougier H, Desrumaux A, Bouchon N, Wroblewski I, Pin I, Nugues F, Mornet E, Baujat G. Enzyme-replacement therapy in perinatal hypophosphatasia: Case report and review of the literature. Arch Pediatr 2018; 25:442-447. [DOI: 10.1016/j.arcped.2018.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/24/2018] [Accepted: 08/15/2018] [Indexed: 11/28/2022]
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Abstract
PURPOSE OF REVIEW Hypophosphatasia (HPP) is a rare genetic disorder caused by mutations of the ALPL gene. ALPL encodes the tissue-non-specific isoenzyme of alkaline phosphatase (TNSALP). Consequently, bone mineralization is decreased leading to fractures, arthralgia, and extra-skeletal manifestations including tissue calcification, respiratory failure, and neurological complications. This review summarizes the most important clinical findings, diagnosis, and treatment options for HPP. RECENT FINDINGS Asfotase alfa is a recombinant human alkaline phosphatase, used as treatment for the underlying cause of HPP. Asfotase alfa enhances the survival in life-threatening HPP and improves bone mineralization, muscle strength, and pulmonary function. However, discontinuation of asfotase alfa leads to reappearance of bone hypomineralization. Due to its varied manifestations, HPP often mimics rheumatological and other bone diseases, thereby delaying its diagnosis. Asfotase alfa, a recombinant alkaline phosphatase, is available for the long-term enzyme replacement therapy in patients with pediatric-onset HPP to treat the bone manifestations of the disease.
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Oyachi M, Harada D, Sakamoto N, Ueyama K, Kondo K, Kishimoto K, Izui M, Nagamatsu Y, Kashiwagi H, Yamamuro M, Tamura M, Kikuchi S, Akiyama T, Michigami T, Seino Y, Namba N. A case of perinatal hypophosphatasia with a novel mutation in the ALPL gene: clinical course and review of the literature. Clin Pediatr Endocrinol 2018; 27:179-186. [PMID: 30083035 PMCID: PMC6073057 DOI: 10.1297/cpe.27.179] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 03/24/2018] [Indexed: 11/28/2022] Open
Abstract
Hypophosphatasia (HPP) is a metabolic bone disease characterized by failure of bone
calcification and vitamin B6 dependent seizures. It is caused by loss-of-function
mutations in the ALPL gene. A newborn girl required respiratory support
by nasal-directional positive airway pressure at birth, and pyridoxine hydrochloride
administration for vitamin B6-dependent seizures observed from day two. Umbilical cord
blood showed low alkaline phosphatase (ALP) activity and high pyridoxal phosphate levels.
Radiographs showed severe rickets-like appearance of the bones. Genetic analysis of the
ALPL gene revealed compound heterozygous mutations,
c.1559delT/p.Ser188Pro. We diagnosed her with perinatal severe HPP, and started the
patient on asfotase alfa from day six. Following enzyme replacement therapy (ERT),
skeletal mineralization and respiratory insufficiency improved with no remarkable
side-effects. Crying vital capacity (CVC) was used to evaluate respiratory status, which
continuously improved from 13.3 mL/kg (day 22) to 20.6 mL/kg (day 113). Since no seizures
occurred, pyridoxine hydrochloride was tapered off at one year of age. Strategies to
manage perinatal severe HPP cases following ERT have not been established till date. A
review of the literature shows that CVC may be a good indicator for weaning from
ventilatory support. In addition, ERT will most likely enable withdrawal of pyridoxine
treatment.
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Affiliation(s)
- Maki Oyachi
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Daisuke Harada
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Natsuko Sakamoto
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Kaoru Ueyama
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Kawai Kondo
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Kanako Kishimoto
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Masafumi Izui
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Yuiko Nagamatsu
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Hiroko Kashiwagi
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Miho Yamamuro
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Makoto Tamura
- Department of Pediatrics and Neonatology, Takatsuki General Hospital, Osaka, Japan
| | - Shin Kikuchi
- Department of Pediatrics and Neonatology, Takatsuki General Hospital, Osaka, Japan
| | - Tomoyuki Akiyama
- Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan
| | - Toshimi Michigami
- Department of Bone and Mineral Research, Research Institute of Osaka Women's and Children's Hospital, Osaka, Japan
| | - Yoshiki Seino
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Noriyuki Namba
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
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Martos-Moreno GÁ, Calzada J, Couce ML, Argente J. Hypophosphatasia: Clinical manifestations, diagnostic recommendations and therapeutic options. An Pediatr (Barc) 2018. [DOI: 10.1016/j.anpede.2017.06.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Dahir KM, Tilden DR, Warner JL, Bastarache L, Smith DK, Gifford A, Ramirez AH, Simmons JS, Black MM, Newman JH, Denny JC. Rare Variants in the Gene ALPL That Cause Hypophosphatasia Are Strongly Associated With Ovarian and Uterine Disorders. J Clin Endocrinol Metab 2018; 103:2234-2243. [PMID: 29659871 PMCID: PMC6456921 DOI: 10.1210/jc.2017-02676] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 04/02/2018] [Indexed: 11/19/2022]
Abstract
Context Mutations in alkaline phosphatase (AlkP), liver/bone/kidney (ALPL), which encodes tissue-nonspecific isozyme AlkP, cause hypophosphatasia (HPP). HPP is suspected by a low-serum AlkP. We hypothesized that some patients with bone or dental disease have undiagnosed HPP, caused by ALPL variants. Objective Our objective was to discover the prevalence of these gene variants in the Vanderbilt University DNA Biobank (BioVU) and to assess phenotypic associations. Design We identified subjects in BioVU, a repository of DNA, that had at least one of three known, rare HPP disease-causing variants in ALPL: rs199669988, rs121918007, and/or rs121918002. To evaluate for phenotypic associations, we conducted a sequential phenome-wide association study of ALPL variants and then performed a de-identified manual record review to refine the phenotype. Results Out of 25,822 genotyped individuals, we identified 52 women and 53 men with HPP disease-causing variants in ALPL, 7/1000. None had a clinical diagnosis of HPP. For patients with ALPL variants, the average serum AlkP levels were in the lower range of normal or lower. Forty percent of men and 62% of women had documented bone and/or dental disease, compatible with the diagnosis of HPP. Forty percent of the female patients had ovarian pathology or other gynecological abnormalities compared with 15% seen in controls. Conclusions Variants in the ALPL gene cause bone and dental disease in patients with and without the standard biomarker, low plasma AlkP. ALPL gene variants are more prevalent than currently reported and underdiagnosed. Gynecologic disease appears to be associated with HPP-causing variants in ALPL.
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Affiliation(s)
- Kathryn M Dahir
- Division of Endocrinology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Daniel R Tilden
- Department of Internal Medicine and Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jeremy L Warner
- Division of Hematology and Oncology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Lisa Bastarache
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Derek K Smith
- Departments of Biostatistics and Oral Maxillofacial Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Aliya Gifford
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Andrea H Ramirez
- Division of Endocrinology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jill S Simmons
- Division of Pediatric Endocrinology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Margo M Black
- Division of Pediatric Endocrinology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - John H Newman
- Division of Allergy, Pulmonary and Critical Care Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Josh C Denny
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, Tennessee
- Division of General Internal Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
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Abstract
We review here clinical, pathophysiological, diagnostic, genetic and molecular aspects of Hypophosphatasia (HPP), a rare inherited metabolic disorder. The clinical presentation is a continuum ranging from a prenatal lethal form with no skeletal mineralization to a mild form with late adult onset presenting with nonpathognomonic symptoms. The prevalence of severe forms is low, whereas less severe forms are more frequently observed. The disease is caused by loss-of-function mutations in the ALPL gene encoding the Tissue Nonspecific Alkaline Phosphatase (TNSALP), a central regulator of mineralization. Severe forms are recessively inherited, whereas moderate forms are either recessively or dominantly inherited, and the more severe the disease is, the more often it is subject to recessive inheritance. The diagnosis is based on a constantly low alkaline phosphatase (AP) activity in serum and genetic testing that identifies ALPL mutations. More than 340 mutations have been identified and are responsible for the extraordinary clinical heterogeneity. A clear but imperfect genotype-phenotype correlation has been observed, suggesting that other genetic or environmental factors modulate the phenotype. Enzyme replacement therapy is now available for HPP, and other approaches, such as gene therapy, are currently being investigated.
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Affiliation(s)
- Etienne Mornet
- Unité de Génétique Constitutionnelle, Service de Biologie, Centre Hospitalier de Versailles, 177 rue de Versailles, 78150 Le Chesnay, France.
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Deeb A, Elfatih A. Could Alerting Physicians for Low Alkaline Phosphatase Levels Be Helpful in Early Diagnosis of Hypophosphatasia? J Clin Res Pediatr Endocrinol 2018; 10:19-24. [PMID: 28766503 PMCID: PMC5838368 DOI: 10.4274/jcrpe.4426] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
OBJECTIVE Hypophosphatasia (HPP) is an inborn error of metabolism with significant morbidity and mortality. Its presentation is nonspecific leading to delayed or missed diagnosis. Low alkaline phosphatase (ALP) is a diagnostic test. Unlike high ALP, low level is commonly not flagged by laboratories as abnormal. A new treatment was shown to be effective in HPP. In this study we aimed to establish the frequency of low ALP levels requiring notification to physicians by the laboratory and also to describe the clinical manifestations of patients presenting with low ALP for a possible diagnosis of HPP. METHODS Patients under age 18 years with low ALP levels were identified from biochemistry records over a period of 6 months. Reference ranges were used as per the Associated Regional and University Pathologists Reference Laboratory (Utah, USA). Electronic results for patients with low levels were checked for flagging as abnormal/low ALP results. Charts of identified patients were reviewed. Presenting features were categorized under groups of disorders. RESULTS ALP levels were tested in 2890 patients. 702 had values less than 160 U/L. Of these patients, 226 (32%) had age/gender specific low ALP. None of the low ALP results was flagged as low. Twenty-one had more than one low reading and their charts were reviewed. Four patients in the neuromuscular and four in the miscellaneous group presented with features consistent with HPP despite these patients having no specific diagnoses. CONCLUSION Laboratories do not alert physicians in cases with low ALP levels. A persistently low level in patients with unspecified diagnoses could be a key to diagnose HPP. Implementing lab-specific ranges and alerting for low levels could prompt physicians to investigate for undiagnosed HPP.
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Affiliation(s)
- Asma Deeb
- Mafraq Hospital, Clinic of Paediatric Endocrinology, Abu Dhabi, United Arab Emirates,* Address for Correspondence: Mafraq Hospital, Clinic of Pediatric Endocrinology, Abu Dhabi, United Arab Emirates Phone: +971 508350568 E-mail:
| | - Abubaker Elfatih
- Shaikh Khalifa Medical City, Clinic of Biochemistry, Abu Dhabi, United Arab Emirates
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49
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Infantile hypophosphatasia combined with vitamin B6-responsive seizures and reticular formation lesions on magnetic resonance imaging: A case report. Brain Dev 2018; 40:140-144. [PMID: 28802630 DOI: 10.1016/j.braindev.2017.07.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 07/21/2017] [Accepted: 07/24/2017] [Indexed: 11/23/2022]
Abstract
BACKGROUND Hypophosphatasia (HPP) is a rare genetic disorder characterized by rachitic bone manifestations and a low serum alkaline phosphatase (ALP) level. It is caused by mutations in the tissue non-specific alkaline phosphatase (TNSALP) gene, which encodes the tissue non-specific isozyme of ALP. HPP patients exhibit various presentations depending on their age at onset, such as infantile HPP combined with vitamin B6-responsive seizures. CASE PRESENTATION A newborn with infantile HPP presented with tonic convulsions from day 5 after birth and received intravenous vitamin B6 (10mg/kg/day pyridoxal phosphate). Eleven days later, frequent apneic episodes occurred, and head magnetic resonance imaging (MRI) showed bilateral reticular formation lesions in the brain stem, including the medulla oblongata. After the pyridoxal phosphate dose was increased (to 40mg/kg/day), the patient's seizures and apnea resolved, and her MRI findings also improved. Genetic testing revealed that she was homozygous for the 1559delT mutation of TNSALP. CONCLUSIONS High-dose pyridoxal phosphate is a useful treatment for HPP-induced seizures and might improve reticular formation lesions.
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50
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Ikenoue S, Miyakoshi K, Ishii T, Sato Y, Otani T, Akiba Y, Kasuga Y, Ochiai D, Matsumoto T, Ichihashi Y, Matsuzaki Y, Tachikawa K, Michigami T, Nishimura G, Ikeda K, Hasegawa T, Tanaka M. Discordant fetal phenotype of hypophosphatasia in two siblings. Am J Med Genet A 2017; 176:171-174. [PMID: 29160033 DOI: 10.1002/ajmg.a.38531] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 10/12/2017] [Accepted: 10/15/2017] [Indexed: 11/11/2022]
Abstract
Hypophosphatasia (HPP) is an autosomal recessive metabolic disorder with impaired bone mineralization due to mutations in the ALPL gene. The genotype-phenotype correlation of this disorder has been widely described. Here, we present two affected siblings, whose fetal phenotypes were discordant. A 31-year-old Japanese woman, G0P0, was referred to our institution because of fetal micromelia. After obstetric counseling, the pregnancy was terminated at 21 weeks' gestation. Post-mortem radiographs demonstrated severely defective mineralization of the skeleton. The calvarial, spinal, and tubular bones were mostly missing. Only the occipital bones, mandible, clavicles, ribs, one thoracic vertebra, ilia, and tibia were relatively well ossified. The radiological findings suggested lethal HPP. Genetic testing for genomic DNA extracted from the umbilical cord identified compound heterozygous mutations in the ALPL gene (c.532T>C, p.Y178H; c.1559delT, p.Leu520Argfs*86). c.532T>C was a novel variant showing no residual activity of the protein by the functional analysis. The parents were heterozygous carriers. In the next pregnancy, biometric values on fetal ultrasonography at 20 and 26 weeks' gestation were normal. At 34 weeks, however, a small chest and shortening of distal long bones came to attention. The neonate delivered at 41 weeks showed serum ALP of <5U/L. Radiological examination showed only mild thoracic hypoplasia and metaphyseal mineralization defects of the long bones. ALP replacement therapy was introduced shortly after birth, and the neonate was discharged at day 22 without respiratory distress. Awareness of discordant fetal phenotypes in siblings with HPP precludes a diagnostic error, and enables early medical intervention to mildly affected neonates.
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Affiliation(s)
- Satoru Ikenoue
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Kei Miyakoshi
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Tomohiro Ishii
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Yu Sato
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Toshimitsu Otani
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Yohei Akiba
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Yoshifumi Kasuga
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Daigo Ochiai
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Tadashi Matsumoto
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
| | - Yosuke Ichihashi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Yohei Matsuzaki
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Kanako Tachikawa
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Toshimi Michigami
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Gen Nishimura
- Department of Pediatric Imaging, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| | - Kazushige Ikeda
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan.,Division of Neonatology, Perinatal Center for Maternal and Child Health, Saitama City Hospital, Saitama, Japan
| | - Tomonobu Hasegawa
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Mamoru Tanaka
- Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan
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