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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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Oto Y, Suzuki D, Morita T, Inoue T, Nitta A, Murakami N, Abe Y, Hamada Y, Akiyama T, Matsubara T. A case report of odonto-hypophosphatasia with a novel variant in the ALPL gene. J Pediatr Endocrinol Metab 2024; 37:276-279. [PMID: 38310522 DOI: 10.1515/jpem-2023-0549] [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: 12/13/2023] [Accepted: 01/16/2024] [Indexed: 02/06/2024]
Abstract
OBJECTIVES Hypophosphatasia (HPP) is a rare skeletal dysplasia caused by variants in the alkaline phosphatase (ALPL) gene. More than 400 pathogenic variants of the ALPL gene have been registered in the ALPL gene variant database. Here, we describe the case of a Japanese child with odonto-hypophsphatasia (odonto-HPP) and a novel ALPL variant. CASE PRESENTATION At the age of 2 years and 1 month, he prematurely lost one deciduous tooth, with the root intact, when he fell and hit his face lightly. Three months later, he lost another adjacent deciduous tooth without incentive. His serum alkaline phosphatase (ALP) level was 72 U/L. His urine phosphoethanolamine (PEA) level was extremely high at 938 μmol/mg·Cre. The serum pyridoxal 5'-phosphaye (PLP) level was 255.9 nmol/L. Based on the clinical symptoms and laboratory findings, the patient was clinically diagnosed with odonto-HPP. Genetic analysis of the ALPL gene revealed a heterozygous variant (NM_000478.6:c.1151C>A, p.Thr384Lys). CONCLUSIONS We report a case of odonto-HPP with a novel variant in the ALPL gene. HPP is a rare disease, and the heterozygous mutation in the ALPL gene highlights the novelty of this case.
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Affiliation(s)
- Yuji Oto
- Department of Pediatrics, Dokkyo Medical University Saitama Medical Center, Saitama, Japan
| | - Daiki Suzuki
- Department of Pediatrics, Dokkyo Medical University Saitama Medical Center, Saitama, Japan
| | - Tsubasa Morita
- Department of Pediatrics, Dokkyo Medical University Saitama Medical Center, Saitama, Japan
| | - Takeshi Inoue
- Child Development and Psychosomatic Medicine Center, Dokkyo Medical University Saitama Medical Center, Saitama, Japan
| | - Akihisa Nitta
- Department of Pediatrics, Dokkyo Medical University Saitama Medical Center, Saitama, Japan
| | - Nobuyuki Murakami
- Department of Pediatrics, Dokkyo Medical University Saitama Medical Center, Saitama, Japan
| | - Yuuka Abe
- Center for Genetic Medicine, Dokkyo Medical University Saitama Medical Center, Saitama, Japan
| | - Yoshinobu Hamada
- Center for Genetic Medicine, Dokkyo Medical University Saitama Medical Center, Saitama, Japan
| | - Tomoyuki Akiyama
- Department of Pediatrics (Child Neurology), Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Okayama, Japan
| | - Tomoyo Matsubara
- Department of Pediatrics, Dokkyo Medical University Saitama Medical Center, Saitama, Japan
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Brandi ML, Khan AA, Rush ET, Ali DS, Al-Alwani H, Almonaei K, Alsarraf F, Bacrot S, Dahir KM, Dandurand K, Deal C, Ferrari SL, Giusti F, Guyatt G, Hatcher E, Ing SW, Javaid MK, Khan S, Kocijan R, Lewiecki EM, Linglart A, M'Hiri I, Marini F, Nunes ME, Rockman-Greenberg C, Seefried L, Simmons JH, Starling SR, Ward LM, Yao L, Brignardello-Petersen R, Roux C. The challenge of hypophosphatasia diagnosis in adults: results from the HPP International Working Group Literature Surveillance. Osteoporos Int 2024; 35:439-449. [PMID: 37982856 DOI: 10.1007/s00198-023-06859-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 07/10/2023] [Indexed: 11/21/2023]
Abstract
Hypophosphatasia (HPP) is an inborn error of metabolism caused by reduced or absent activity of the tissue non-specific alkaline phosphatase (TNSALP) enzyme, resulting from pathogenic variants in the ALPL gene. Clinical presentation of HPP is highly variable, including lethal and severe forms in neonates and infants, a benign perinatal form, mild forms manifesting in adulthood, and odonto-HPP. Diagnosis of HPP remains a challenge in adults, as signs and symptoms may be mild and non-specific. Disease presentation varies widely; there are no universal signs or symptoms, and the disease often remains underdiagnosed or misdiagnosed, particularly by clinicians who are not familiar with this rare disorder. The absence of diagnosis or a delayed diagnosis may prevent optimal management for patients with this condition. Formal guidelines for the diagnosis of adults with HPP do not exist, complicating efforts for consistent diagnosis. To address this issue, the HPP International Working Group selected 119 papers that explicitly address the diagnosis of HPP in adults through a Medline, Medline In-Process, and Embase search for the terms "hypophosphatasia" and "HPP," and evaluated the pooled prevalence of 17 diagnostic characteristics, initially selected by a group of HPP clinical experts, in eligible studies and in patients included in these studies. Six diagnostic findings showed a pooled prevalence value over 50% and were considered for inclusion as major diagnostic criteria. Based on these results and according to discussion and consideration among members of the Working Group, we finally defined four major diagnostic criteria and five minor diagnostic criteria for HPP in adults. Authors suggested the integrated use of the identified major and minor diagnostic criteria, which either includes two major criteria, or one major criterion and two minor criteria, for the diagnosis of HPP in adults.
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Affiliation(s)
- Maria Luisa Brandi
- F.I.R.M.O. Italian Foundation for the Research On Bone Diseases, Florence, Italy.
- Donatello Bone Clinic, Villa Donatello Hospital, Florence, Italy.
| | - Aliya A Khan
- Division of Endocrinology and Metabolism, McMaster University, Hamilton, Canada
| | - Eric T Rush
- Division of Clinical Genetics, Children's Mercy Kansas City and Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, MO, USA
- Division of Endocrinology, Metabolism, Osteoporosis, and Genetics, Department of Internal Medicine, University of Kansas School of Medicine, Kansas City, KS, USA
| | - Dalal S Ali
- Division of Endocrinology and Metabolism, McMaster University, Hamilton, Canada
| | - Hatim Al-Alwani
- Division of Endocrinology and Metabolism, McMaster University, Hamilton, Canada
| | - Khulod Almonaei
- Division of Endocrinology and Metabolism, McMaster University, Hamilton, Canada
| | - Farah Alsarraf
- Division of Endocrinology and Metabolism, McMaster University, Hamilton, Canada
| | - Severine Bacrot
- Department of Genetics, Centre Hospitalier de Versailles, Hôpital André Mignot, Versailles, France
| | - Kathryn M Dahir
- Division of Endocrinology and Metabolism, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Karel Dandurand
- Department of Medicine, Endocrinology and Metabolism, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Chad Deal
- Center for Osteoporosis and Metabolic Bone Disease, Department of Rheumatology, The Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Serge Livio Ferrari
- Division of Bone Diseases, Department of Internal Medicine Specialties, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland
| | - Francesca Giusti
- Donatello Bone Clinic, Villa Donatello Hospital, Florence, Italy
| | - Gordon Guyatt
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada
| | - Erin Hatcher
- Neuromuscular Clinic, McMaster University Medical Centre, Hamilton Health Sciences, Hamilton, ON, Canada
| | - Steven W Ing
- Division of Endocrinology, Diabetes, & Metabolism, Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Muhammad Kassim Javaid
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Sarah Khan
- Bone Research and Education Centre, Oakville, ON, Canada
| | - Roland Kocijan
- Trauma Centre Meidling, Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA, 1St Medical Department Hanusch Hospital, 1140, Vienna, Austria
| | - E Michael Lewiecki
- New Mexico Clinical Research & Osteoporosis Center, Albuquerque, NM, USA
| | - Agnes Linglart
- APHP, Bicêtre Paris-Sud, University Paris Sud, Paris-Saclay, Le Kremlin Bicêtre, Paris, France
| | - Iman M'Hiri
- Bone Research and Education Centre, Oakville, ON, Canada
| | - Francesca Marini
- F.I.R.M.O. Italian Foundation for the Research On Bone Diseases, Florence, Italy
| | - Mark E Nunes
- Division of Medical Genetics and Metabolism, Valley Children's HealthCare, Madera, CA, USA
| | | | - Lothar Seefried
- Musculoskeletal Center Würzburg, University of Würzburg, Würzburg, Germany
| | - Jill H Simmons
- Division of Endocrinology and Metabolism, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Susan R Starling
- Division of Clinical Genetics, Children's Mercy Kansas City and Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, MO, USA
| | - Leanne M Ward
- Department of Pediatrics, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, ON, Canada
| | - Liang Yao
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada
| | | | - Christian Roux
- INSERM CRESS UMR 1153, Paris, France
- Université Paris-Cité, Department of Rheumatology, APHP-Centre, Cochin Hospital, Paris, France
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Baroncelli GI, Carlucci G, Freri E, Giuca MR, Guarnieri V, Navarra G, Toschi B, Mora S. The diagnosis of hypophosphatasia in children as a multidisciplinary effort: an expert opinion. J Endocrinol Invest 2024; 47:739-747. [PMID: 37752373 PMCID: PMC10904512 DOI: 10.1007/s40618-023-02199-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 09/12/2023] [Indexed: 09/28/2023]
Abstract
Hypophosphatasia (HPP) is a rare genetic disorder in which pathogenic variants of the ALPL gene lead to a marked decrease of tissue non-specific alkaline phosphatase (TNSALP) activity. Although HPP is a systemic disorder, its clinical manifestations are more evident on bones, teeth, muscle and central nervous system. The clinical spectrum ranges from severe forms with extreme skeletal deformities, respiratory impairment, seizures, to very mild forms with onset in late adulthood and few clinical signs. The diagnosis can be suspected by measurement of TNSALP activity, but the insufficient awareness among health professionals and the lack of official guidelines are responsible for delayed diagnosis in children with HPP. The purpose of the current document is to provide an expert opinion directed at optimizing the diagnostic pathway of pediatric HPP. From April to December 2022, a multidisciplinary working group of 6 experts including two pediatric endocrinologists, a pediatric neurologist, a pediatric odontologist, a clinical geneticist, and a molecular biologist gathered in a series of periodic meetings to discuss the main issues related to the diagnosis of HPP in children and formalize an Expert Opinion statement. The experts agreed on a diagnostic trail that begins with the recognition of specific clinical signs, leading to biochemical analyses of TNSALP activity and vitamin B6 serum concentration. Very important are the neurological and dental manifestation of the disease that should be thoroughly investigated. The evaluation of TNSALP activity must consider sex and age variability and low activity must be persistent. Repeated blood measurements are thus necessary. The molecular analysis is then mandatory to confirm the diagnosis and for genetic counseling.
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Affiliation(s)
- G I Baroncelli
- Pediatric and Adolescent Endocrinology, Division of Pediatrics, Department of Obstetrics, Gynecology and Pediatrics, University Hospital, Pisa, Italy
| | - G Carlucci
- OPT S.P.A., Soluzioni Per Il Mondo Healthcare, Milan, Italy
| | - E Freri
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - M R Giuca
- Unit of Pediatric Dentistry, Department of Surgical Medical Molecular Pathology and Critical Area, Dental and Oral Surgery Clinic, University of Pisa, Pisa, Italy
| | - V Guarnieri
- Division of Medical Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, Foggia, Italy
| | - G Navarra
- OPT S.P.A., Soluzioni Per Il Mondo Healthcare, Milan, Italy
| | - B Toschi
- Section of Medical Genetics, Department of Medical and Oncological Area, University Hospital, Pisa, Italy
| | - S Mora
- Laboratory of Pediatric Endocrinology, Department of Pediatrics, IRCCS San Raffaele Hospital, Milan, Italy.
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5
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Aljuraibah F, Alalwan I, Habeb A. Diagnostic and New Therapeutic Approaches to Two Challenging Pediatric Metabolic Bone Disorders: Hypophosphatasia and X-linked Hypophosphatemic Rickets. Curr Pediatr Rev 2024; 20:395-404. [PMID: 37927073 DOI: 10.2174/0115733963206838231031102750] [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: 01/23/2023] [Revised: 06/09/2023] [Accepted: 10/03/2023] [Indexed: 11/07/2023]
Abstract
The diagnosis and management of metabolic bone disease among children can be challenging. This difficulty could be due to many factors, including limited awareness of these rare conditions, the complex pathophysiology of calcium and phosphate homeostasis, the overlapping phenotype with more common disorders (such as rickets), and the lack of specific treatments for these rare disorders. As a result, affected individuals could experience delayed diagnosis or misdiagnosis, leading to improper management. In this review, we describe the challenges facing diagnostic and therapeutic approaches to two metabolic bone disorders (MBD) among children: hypophosphatasia (HPP) and X-linked hypophosphatemia (XLH). We focus on explaining the pathophysiological processes that conceptually underpin novel therapeutic approaches, as well as these conditions' clinical or radiological similarity to nutritional rickets. Particularly in areas with limited sun exposure and among patients not supplementing vitamin D, nutritional rickets are still more common than HPP and XLH, and pediatricians and primary physicians frequently encounter this disorder in their practices. More recently, our understanding of these disorders has significantly improved, leading to the development of novel therapies. Asfotas alfa, a recombinant, human- tissue, nonspecific alkaline phosphatase, improved the survival of patients with HPP. Burosumab, a human monoclonal anti-FGF23 antibody, was recently approved as a specific therapy for XLH. We also highlight the current evidence on these two specific therapies' safety and effectiveness, though long-term data are still needed. Both HPP and XLH are multisystemic disorders that should be managed by multidisciplinary teams. Finally, recognizing these conditions in early stages will enable affected children and young adults to benefit from newly introduced, specific therapies.
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Affiliation(s)
- Fahad Aljuraibah
- Department of Pediatrics, King Abdullah Specialist Children's Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
- College of Medicine, King Saud bin Abdul-Aziz University for Health Sciences, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
- King Abdullah International Medical Research Center, Ministry of National Guard Health Affairs Riyadh, Saudi Arabia
| | - Ibrahim Alalwan
- Department of Pediatrics, King Abdullah Specialist Children's Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
- College of Medicine, King Saud bin Abdul-Aziz University for Health Sciences, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
- King Abdullah International Medical Research Center, Ministry of National Guard Health Affairs Riyadh, Saudi Arabia
| | - Abdelhadi Habeb
- Department of Pediatrics, Prince Mohammed bin Abdulaziz Hospital for National Guard, Al-Madinah, Saudi Arabia
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6
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Loret A, Jacob C, Mammou S, Bigot A, Blasco H, Audemard-Verger A, Schwartz IV, Mulleman D, Maillot F. Joint manifestations revealing inborn metabolic diseases in adults: a narrative review. Orphanet J Rare Dis 2023; 18:239. [PMID: 37563694 PMCID: PMC10416490 DOI: 10.1186/s13023-023-02810-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 07/06/2023] [Indexed: 08/12/2023] Open
Abstract
Inborn metabolic diseases (IMD) are rare conditions that can be diagnosed during adulthood. Patients with IMD may have joint symptoms and the challenge is to establish an early diagnosis in order to institute appropriate treatment and prevent irreversible damage. This review describes the joint manifestations of IMD that may be encountered in adults. The clinical settings considered were arthralgia and joint stiffness as well as arthritis. Unspecific arthralgias are often the first symptoms of hereditary hemochromatosis, chronic low back pain may reveal an intervertebral disc calcification in relation with alkaptonuria, and progressive joint stiffness may correspond to a mucopolysaccharidosis or mucolipidosis. Gaucher disease is initially revealed by painful acute attacks mimicking joint pain described as "bone crises". Some IMD may induce microcrystalline arthropathy. Beyond classical gout, there are also gouts in connection with purine metabolism disorders known as "enzymopathic gouts". Pyrophosphate arthropathy can also be part of the clinical spectrum of Gitelman syndrome or hypophosphatasia. Oxalate crystals arthritis can reveal a primary hyperoxaluria. Destructive arthritis may be indicative of Wilson's disease. Non-destructive arthritis may be seen in mevalonate kinase deficiency and familial hypercholesterolemia.
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Affiliation(s)
- Amaury Loret
- Department of Internal Medicine, University Hospital of Tours, Tours, France.
- Department of Rheumatology, University Hospital of Tours, Tours, France.
- Department of Internal Medicine, Hôpital Bretonneau, 2 Boulevard Tonnellé, CHRU de Tours, Tours cedex, 37044, France.
| | - Claire Jacob
- Department of Internal Medicine, University Hospital of Tours, Tours, France
| | - Saloua Mammou
- Department of Rheumatology, University Hospital of Tours, Tours, France
| | - Adrien Bigot
- Department of Internal Medicine, University Hospital of Tours, Tours, France
| | - Hélène Blasco
- Biochemistry laboratory, University Hospital of Tours, Tours, France
- UMR INSERM 1253, Tours, France
- Reference center for inherited metabolic diseases, Tours, France
| | | | - Ida Vd Schwartz
- Medical Genetics Service/Genetics Department, Hospital de Clinicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre - RS, Brazil
| | - Denis Mulleman
- Department of Rheumatology, University Hospital of Tours, Tours, France
| | - François Maillot
- Department of Internal Medicine, University Hospital of Tours, Tours, France
- UMR INSERM 1253, Tours, France
- Reference center for inherited metabolic diseases, Tours, France
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Tachikawa K, Yamazaki M, Michigami T. A unique case of childhood hypophosphatasia caused by a novel heterozygous 51-bp in-frame deletion in the ALPL gene. Clin Pediatr Endocrinol 2023; 32:180-187. [PMID: 37362163 PMCID: PMC10288296 DOI: 10.1297/cpe.2023-0019] [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: 03/13/2023] [Accepted: 04/18/2023] [Indexed: 06/28/2023] Open
Abstract
Hypophosphatasia (HPP) is caused by inactivating variants of the ALPL gene, which encodes tissue non-specific alkaline phosphatase (TNSALP). Among the six subtypes of HPP, childhood HPP presents after 6 months and before 18 yr of age, and is inherited in both autosomal dominant and autosomal recessive manners. Patients with childhood HPP have variable symptoms, including rickets-like bone changes, low bone mineral density (BMD), short stature, muscle weakness, craniosynostosis, and premature loss of deciduous teeth. Here, we describe a 7-yr-old boy with childhood HPP who showed short stature, impaired ossification of the carpal bones, and low BMD. Genetic testing identified a novel heterozygous 51-bp in-frame deletion in the ALPL gene (c.1482_1532del51), leading to the lack of 17 amino acids between Gly495 and Leu511 (p.Gly495_Leu511del). In vitro transfection experiments revealed the loss of enzymatic activity and the dominant-negative effect of the TNSALP[p.Gly495_Leu511del] variant; thus, the patient was diagnosed as having autosomal dominant HPP. The TNSALP[p.Gly495_Leu511del] variant was localized to the plasma membrane as was the wild-type TNSALP (TNSALP[WT]): however, co-immunoprecipitation experiments suggested a reduced dimerization between TNSALP[p.Gly495_Leu511del] and TNSALP[WT]. This case expands the variable clinical manifestation of childhood HPP and sheds light on the molecular bases underlying the dominant-negative effects of some TNSALP variants.
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Affiliation(s)
- Kanako Tachikawa
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka Prefectural Hospital Organization, Osaka, Japan
| | - Miwa Yamazaki
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka Prefectural Hospital Organization, Osaka, Japan
| | - Toshimi Michigami
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka Prefectural Hospital Organization, Osaka, Japan
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Kim I, Noh ES, Kim MS, Jang JH, Jeon TY, Choi HW, Cho SY. Six-year clinical outcomes of enzyme replacement therapy for perinatal lethal and infantile hypophosphatasia in Korea: Two case reports. Medicine (Baltimore) 2023; 102:e32800. [PMID: 36820543 PMCID: PMC9907957 DOI: 10.1097/md.0000000000032800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
INTRODUCTION Hypophosphatasia (HPP) is a genetic disease caused by loss-of-function mutations in ALPL, which encodes tissue-nonspecific alkaline phosphatase (ALP). Early diagnosis and treatment of perinatal and infantile HPP are important because of their high mortality rates. Enzyme replacement therapy (ERT) using human recombinant tissue-nonspecific ALP asfotase alfa was introduced in Korea in 2016. We report the first experience of ERT over 6 years for perinatal lethal and infantile HPP in Korea. PATIENT CONCERNS The first patient was a 6-week-old Korean boy with a failure to thrive. The second patient was an 8-day-old Korean-Uzbek body with generalized tonic-clonic seizure with cyanosis. DIAGNOSES HPP was suspected in both patients because of the very low level of ALP activity and rachitic findings on radiographs, and the disease was confirmed by Sanger sequencing of the ALPL gene. INTERVENTION The first patient with infantile HPP started ERT at 21 months of age and the second patient with perinatal HPP started ERT at 30 days of age. Both patients received asfotase alfa (2 mg/kg 3 times per week subcutaneously, adjusted to 3 mg/kg 3 times per week if required) for 6 years. OUTCOMES After 6 years of ERT, radiographic findings and growth standard deviation scores improved in both patients. The second patient showed no evidence of rickets after 3 years of ERT. Mechanical respiratory support and supplemental oxygen were not required after 4.5 years of treatment in the first patient and at 2 months after treatment in the second patient. CONCLUSION Among the 2 patients, the patient who started ERT early had a much better prognosis despite a more severe initial clinical presentation. Our results suggest that early diagnosis and prompt treatment play an important role in improving long-term prognosis and avoiding morbidity and premature mortality in patients with perinatal and infantile HPP.
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Affiliation(s)
- Insung Kim
- Department of Public Health Administration, Asan City Health Center, Asan, Korea
| | - Eu-Seon Noh
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Min-Sun Kim
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ja-Hyun Jang
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Tae Yeon Jeon
- Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hae Won Choi
- Department of Orthodontics, The Institute of Oral Health Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Sung Yoon Cho
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
- * Correspondence: Sung Yoon Cho, Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 06351, Korea (e-mail: )
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Sadhukhan S, Mehta P, Rajender S, Gupta SK, Chattopadhyay N. Proposing a clinical algorithm for better diagnosis of hypophosphatasia in resource-limiting situations. Osteoporos Int 2022; 33:2479-2493. [PMID: 35776147 DOI: 10.1007/s00198-022-06480-1] [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: 01/07/2022] [Accepted: 06/16/2022] [Indexed: 10/17/2022]
Abstract
Early diagnosis of hypophosphatasia (HPP) is challenging. Here, we propose to broaden the diagnostic criteria of HPP by reviewing published data on BMD and fractures in HPP patients. Non-osteoporotic fractures and higher than normal lumbar BMD were recurrent in HPP patients and could be included as diagnostic criteria. HPP is a genetic disorder caused by autosomal recessive or dominant loss-of-function mutations in the ALPL gene that encodes for tissue-nonspecific alkaline phosphatase (TNSALP). Expressive genetic heterogeneity and varying severity of TNSALP deficiency lead to a wide-ranging presentation of skeletal diseases at different ages that coupled with HPP's rarity and limitation of biochemical and mutational studies present serious hurdles to early diagnosis and management of HPP. To widen the scope of HPP diagnosis, we assessed the possibility of areal bone mineral density (BMD) as an additional clinical feature of this disease. PubMed, Web of Science, and ScienceDirect were searched with the following keywords: ("Hypophosphatasia OR HPP") AND ("Bone Mineral Density OR BMD") AND "Human". Studies and case reports of subjects with age ≥ 18 years and having BMD data were included. We pooled data from 25 publications comprising 356 subjects (90 males, 266 females). Only four studies had a control group. Biochemical hallmarks, pyridoxal 5'-phosphate (PLP) and phosphoethanolamine (PEA), were reported in fifteen and six studies, respectively. Twenty studies reported genetic data, nineteen studies reported non-vertebral fractures, all studies reported lumbar spine (LS) BMD, and nineteen reported non-vertebral BMD. Higher than normal and normal BMD at LS were reported in three and two studies, respectively. There was marked heterogeneity in BMD at the non-vertebral sites. Higher than normal or normal LS BMD in an adult with minimal or insufficient fractures, pseudofractures, non-healing fractures, fragility fractures, and stress fractures may be included in the diagnostic protocol of HPP. However, genetic testing is recommended for a definitive diagnosis.
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Affiliation(s)
- Sreyanko Sadhukhan
- Division of Endocrinology and Centre for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI), CSIR-Central Drug Research Institute, Lucknow, India
- Academy of Scientific and Innovative Research, Ghaziabad, 201002, India
| | - Poonam Mehta
- Division of Endocrinology and Centre for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI), CSIR-Central Drug Research Institute, Lucknow, India
- Academy of Scientific and Innovative Research, Ghaziabad, 201002, India
| | - Singh Rajender
- Division of Endocrinology and Centre for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI), CSIR-Central Drug Research Institute, Lucknow, India
- Academy of Scientific and Innovative Research, Ghaziabad, 201002, India
| | - Sushil Kumar Gupta
- Department of Endocrinology, Sanjay Gandhi Post-Graduate Institute of Medical Sciences, Lucknow, India
| | - Naibedya Chattopadhyay
- Division of Endocrinology and Centre for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI), CSIR-Central Drug Research Institute, Lucknow, India.
- Academy of Scientific and Innovative Research, Ghaziabad, 201002, India.
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10
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Beck NM, Sagaser KG, Lawson CS, Hertenstein C, Jachens A, Forster KR, Miller KA, Jelin AC, Blakemore KJ, Hoover‐Fong J. Not just a carrier: Clinical presentation and management of patients with heterozygous disease-causing alkaline phosphatase (ALPL) variants identified through expanded carrier screening. Mol Genet Genomic Med 2022; 11:e2056. [PMID: 36444396 PMCID: PMC9834184 DOI: 10.1002/mgg3.2056] [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: 01/21/2022] [Revised: 07/05/2022] [Accepted: 09/01/2022] [Indexed: 12/02/2022] Open
Abstract
Hypophosphatasia (HPP) is an underrecognized, complex bone mineralization disorder with variable manifestations caused by one or two deleterious variants in the alkaline phosphatase (ALPL) gene. Expanded carrier screening (ECS), inclusive of ALPL, intends to inform reproductive risk but may incidentally reveal an HPP diagnosis with 50% familial risks. We sought to investigate at-risk individuals and develop a multidisciplinary referral and evaluation protocol for ECS-identified ALPL heterozygosity. A retrospective database query of ECS results from 8 years to 1 month for heterozygous pathogenic/likely pathogenic ALPL variants was completed. We implemented a clinical protocol for diagnostic testing and imaging, counseling, and interdisciplinary care management for identified patients, and outcomes were documented. Heterozygous ALPL variants were identified in 12/2248 unrelated patients undergoing ECS (0.53%; heterozygote frequency 1/187). Of 10 individuals successfully contacted, all demonstrated symptomatology and/or alkaline phosphatase values consistent with HPP. ECS may reveal incidental health risks, including recognition of missed HPP diagnoses in ALPL heterozygotes. In our cohort, all ECS-identified ALPL heterozygotes with clinical and/or biochemical data available demonstrated features of HPP. Referral to a genetics professional familiar with HPP is indicated for family history assessment, genetic counseling, cascade testing, and long-term bone health management.
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Affiliation(s)
- Natalie M. Beck
- Greenberg Center for Skeletal Dysplasias, Department Genetic of MedicineJohns Hopkins University School of MedicineBaltimoreMarylandUSA,Genome Medical ServicesSan FranciscoCaliforniaUSA
| | - Katelynn G. Sagaser
- Division of Maternal Fetal Medicine, Department of Gynecology and ObstetricsJohns Hopkins University School of MedicineBaltimoreMarylandUSA,JunoDxSan DiegoCaliforniaUSA
| | - Cathleen S. Lawson
- Division of Maternal Fetal Medicine, Department of Gynecology and ObstetricsJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Christine Hertenstein
- Division of Maternal Fetal Medicine, Department of Gynecology and ObstetricsJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Ashley Jachens
- Center for Maternal and Fetal MedicineHoward County General Hospital, Johns Hopkins HospitalBaltimoreMarylandUSA
| | - Katherine R. Forster
- Center for Fetal TherapyJohns Hopkins University School of MedicineBaltimoreMarylandUSA,Sibley Memorial Hospital Maternal Fetal MedicineWashingtonDistrict of ColumbiaUSA
| | - Kristen A. Miller
- Division of Maternal Fetal Medicine, Department of Gynecology and ObstetricsJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Angie C. Jelin
- Division of Maternal Fetal Medicine, Department of Gynecology and ObstetricsJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Karin J. Blakemore
- Division of Maternal Fetal Medicine, Department of Gynecology and ObstetricsJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Julie Hoover‐Fong
- Greenberg Center for Skeletal Dysplasias, Department Genetic of MedicineJohns Hopkins University School of MedicineBaltimoreMarylandUSA
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11
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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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12
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Shajani-Yi Z, Ayala-Lopez N, Black M, Dahir KM. Urine phosphoethanolamine is a specific biomarker for hypophosphatasia in adults. Bone 2022; 163:116504. [PMID: 35878747 DOI: 10.1016/j.bone.2022.116504] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/04/2022] [Accepted: 07/19/2022] [Indexed: 11/02/2022]
Abstract
OBJECTIVES We investigated the utility of urine phosphoethanolamine (PEA) as a marker to aid in diagnosing and/or confirming hypophosphatasia (HPP) in adults and for monitoring patients on enzyme replacement therapy (ERT). METHODS Data was collected from seventy-eight adults who were referred to the Vanderbilt Program for Metabolic Bone Disease for evaluation of a possible or confirmatory HPP diagnosis between July 2014 through December 2019. Fifty-nine patients were diagnosed with HPP and nineteen were excluded from a diagnosis of HPP. The urine PEA results of those patients with a confirmed diagnosis of HPP and those patients with a diagnosis of HPP excluded were captured and compared to other laboratory and clinical parameters consistent with HPP, including alkaline phosphatase (ALP) activity, plasma pyridoxal 5'-phosphate (PLP), the presence of musculoskeletal abnormalities, and genetic testing for pathogenic mutations in ALPL. RESULTS Initial urine PEA values in patients in our HPP cohort and not on ERT were significantly higher (median = 150.0 nmol/mg creatinine, IQR = 82.0-202.0) compared patients in our HPP negative group (median 18.0 nmol/mg creatinine, IQR = 14.0-30.0, p < 0.0001) and higher than patients on ERT (median 65.0 nmol/mg creatinine, IQR = 45.3-79.8). Patients who began ERT had a decline in urine PEA levels after treatment with a mean decrease of 68.1 %. Plasma ALP levels were significantly lower in the group of patients with HPP and not on ERT group (median = 24.0 U/L, IQR = 15.0-29.50) compared to the patients without HPP (median = 45.50 U/L, IQR = 34.0-62.0;) and plasma PLP levels were significantly higher in the HPP non-ERT group (median = 284.0 nmol/L, IQR = 141.0-469.4) compared to the patients without HPP (median = 97.5 nmol/L, IQR = 43.7-206.0;). The area under the curve (AUC) of urine PEA, ALP, and PLP to distinguish between HPP and non-HPP patients is 0.968, 0.927 and 0.781, respectively, in our cohort. Urine PEA had 100 % specificity (95 % CI of 83.2 % to 100.0 %) for diagnosing HPP at a value >53.50 nmol/mg creatinine with a sensitivity of 88.4 %; 95%CI 75.5 to 94.9 %. ALP had a 100 % specificity (95 % CI of 82.4 % to 100.0 %) for diagnosing HPP at a value <30.5 U/L with a sensitivity of 77.2 %; (95%CI 64.8 to 86.2 %). PLP had a 100 % specificity (95 % CI of 81.6 % to 100.0 %) for diagnosing HPP at a value >436 nmol/L with a sensitivity of 26.9 %; (95%CI 16.8 to 40.3 %). The most common pathogenic or likely pathogenic mutations in our cohort were c.1250A>G (p.Asn417Ser), c.1133A>T (p.Asp378Val), c.881A>C (p.Asp294Ala), c.1171C>T (p.Arg391Cys), and c.571G>A, (p.Glu191Lys). CONCLUSIONS Urine PEA is a promising diagnostic and confirmatory marker for HPP in patients undergoing investigation for HPP. Urine PEA also has potential use as a marker to monitor ERT compliance. Future studies are necessary to evaluate the association between PEA levels and clinical outcomes.
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Affiliation(s)
- Zahra Shajani-Yi
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Nadia Ayala-Lopez
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Margo Black
- Division of Endocrinology, Program for Metabolic Bone Disorders, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Kathryn McCrystal Dahir
- Division of Endocrinology, Program for Metabolic Bone Disorders, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
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13
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Siami H, Parsamanesh N, Besharati Kivi S. Young woman with hypophosphatasia: A case report. Clin Case Rep 2022; 10:e05633. [PMID: 35356190 PMCID: PMC8958189 DOI: 10.1002/ccr3.5633] [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: 01/26/2022] [Revised: 02/23/2022] [Accepted: 03/09/2022] [Indexed: 11/11/2022] Open
Abstract
Hypophosphatasia is a rare inherited disease defined by teeth and bone mineralization impairment leading to depletion of tissue non-specific alkaline phosphatase. We define a young woman diagnosed with hypophosphatasia (after several times alkaline phosphatase levels were low) was discovered following femoral fracture. A 30-year-old woman who presented for a history of early permanent teeth loss during the last 5 years and HPP-like symptoms in family history and bone radiograph verified bowing, deficient mineralization, and symmetrical subtrochanteric stress fractures of femurs was referred to our clinic for further management. Blood test findings defined raised phosphorus levels on two occasions at 6.2 and 5.7 mg/dl and insufficient 25-hydroxy vitamin D level. HPP early diagnosis and adequate treatment, depending on the clinical symptoms along with laboratory tests, could be effective in decreasing the suffering of the disease and side effects.
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Affiliation(s)
- Haleh Siami
- School of MedicineIslamic Azad University of Medical ScienceTehranIran
| | - Negin Parsamanesh
- Zanjan Metabolic Diseases Research CenterZanjan University of Medical ScienceZanjanIran
| | - Shahin Besharati Kivi
- Zanjan Metabolic Diseases Research CenterZanjan University of Medical ScienceZanjanIran
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14
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Sugiyama Y, Watanabe T, Tajika M, Matsuhashi T, Shimura M, Fushimi T, Ichimoto K, Matsunaga A, Ebihara T, Tsuruoka T, Akiyama T, Murayama K. A Japanese single-center experience of the efficacy and safety of asfotase alfa in pediatric-onset hypophosphatasia. Orphanet J Rare Dis 2022; 17:78. [PMID: 35197081 PMCID: PMC8867653 DOI: 10.1186/s13023-022-02230-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 02/06/2022] [Indexed: 11/10/2022] Open
Abstract
Background Hypophosphatasia (HPP) is a rare inherited metabolic disorder caused by mutations in the ALPL gene, which encodes tissue nonspecific alkaline phosphatase. The severity of HPP is widely diverse from the perinatal form to the adult mild form. The former represents the most severe form and was earlier associated with high mortality due to pneumonia which was caused by severe hypomineralization of the bones—such as chest deformity and fractured ribs—and muscle weakness. Enzyme replacement therapy using asfotase alfa (AA) was approved in 2015 in Japan for treating patients with HPP and has improved their pulmonary function and life prognosis. There are several practical and ethical challenges related to using orphan drugs for a rare disorder in a publicly funded healthcare system. Sharing experiences about their application is essential towards formulating guidelines to assist clinicians with decisions about their initiation and withdrawal. We report the details of AA experience in ten cases of pediatric-onset HPP in nine families from January 2015 to November 2019 (median [interquartile range] age 11.0 [7.6–12.5] years; 60% male). This is a study of a single-center cohort describing the clinical course of patients with HPP, mainly consisting of the mild childhood form of HPP, treated with AA in Japan. Results One case of perinatal form of HPP, two cases of benign prenatal form, and seven cases of childhood form were observed. The most common symptom at onset was pain. All patients had low serum alkaline phosphatase levels as compared to the age-matched reference range before the commencement of AA. All HPP patients seem to have responded to AA treatment, as evidenced by pain alleviation, increased height standard deviation, improvement in respiratory condition and 6-min walk test result improvement, disappearance of kidney calcification, alleviation of fatigue, and/or increases in bone mineralization. There were no serious adverse events, but all patients had an injection site reaction and skin changes at the injection sites. Genetic analysis showed that eight out of ten patients had compound heterozygosity. Conclusions AA may be effective in patients with mild to severe pediatric-onset forms of HPP. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-022-02230-y.
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Affiliation(s)
- Yohei Sugiyama
- Center for Medical Genetics, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba City, Chiba Prefecture, 266-0007, Japan.,Department of Metabolism, Chiba Children's Hospital, Chiba, Japan.,Department of Neonatology, Chiba Children's Hospital, Chiba, Japan
| | - Taijiro Watanabe
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Makiko Tajika
- Center for Medical Genetics, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba City, Chiba Prefecture, 266-0007, Japan.,Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Tetsuro Matsuhashi
- Center for Medical Genetics, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba City, Chiba Prefecture, 266-0007, Japan.,Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Masaru Shimura
- Center for Medical Genetics, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba City, Chiba Prefecture, 266-0007, Japan.,Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Takuya Fushimi
- Center for Medical Genetics, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba City, Chiba Prefecture, 266-0007, Japan.,Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Keiko Ichimoto
- Center for Medical Genetics, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba City, Chiba Prefecture, 266-0007, Japan.,Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Ayako Matsunaga
- Center for Medical Genetics, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba City, Chiba Prefecture, 266-0007, Japan.,Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Tomohiro Ebihara
- Center for Medical Genetics, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba City, Chiba Prefecture, 266-0007, Japan.,Department of Neonatology, Chiba Children's Hospital, Chiba, Japan
| | - Tomoko Tsuruoka
- Center for Medical Genetics, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba City, Chiba Prefecture, 266-0007, Japan.,Department of Neonatology, Chiba Children's Hospital, Chiba, Japan
| | - Tomoyuki Akiyama
- Department of Child Neurology, Okayama University Hospital, 2-5-1 Shikata-cho, Kita-ku, Okayama city, Okayama Prefecture, 700-8558, Japan
| | - Kei Murayama
- Center for Medical Genetics, Chiba Children's Hospital, 579-1 Heta-cho, Midori-ku, Chiba City, Chiba Prefecture, 266-0007, Japan. .,Department of Metabolism, Chiba Children's Hospital, Chiba, Japan.
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15
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Evaluation of alveolar bone hypomineralization in pediatric hypophosphatasia using orthopantomography. Sci Rep 2022; 12:1211. [PMID: 35075203 PMCID: PMC8786966 DOI: 10.1038/s41598-022-05171-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 01/07/2022] [Indexed: 12/15/2022] Open
Abstract
Hypophosphatasia (HPP) is a metabolic disease characterized by impaired bone mineralization and early exfoliation of primary teeth. This study was performed to develop a method for quantitatively evaluating alveolar bone hypomineralization using orthopantomographic images. Alveolar bone density was defined according to the pixel values and corrected by brightness shown by an indicator applied to the orthopantomographic device. Images of 200 healthy subjects (aged 2-15 years) were classified into five age groups. The corrected pixel values were significantly lower in the younger group than in those aged 14-15 years (2-4, 5-7, and 8-10 years versus 14-15 years: P < 0.0001, 11-13 years versus 14-15 years: P < 0.01). Orthopantomographic images of 17 patients with HPP were evaluated. The corrected pixel values of three-fourths of the patients with odonto type HPP were lower than the mean values of the healthy group. One-third of patients treated with enzyme replacement therapy showed higher corrected pixel values than the healthy group. Our results suggest that odonto type HPP without skeletal problems is occasionally accompanied by hypomineralization of alveolar bone and that alveolar bone hypomineralization in patients with severe HPP is possibly improved by enzyme replacement therapy.
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16
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Christidis G, Martin T, Walter F, Lammert F, Krawczyk M. Hypophosphatasia: An Underappreciated Cause of Atraumatic Stress Fractures. Am J Med 2022; 135:e18-e19. [PMID: 34543646 DOI: 10.1016/j.amjmed.2021.08.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/12/2021] [Accepted: 08/21/2021] [Indexed: 11/17/2022]
Affiliation(s)
- Grigorios Christidis
- Department of Medicine II, Saarland University Medical Center, Saarland University, Homburg, Germany
| | - Thomas Martin
- Laboratory of Human Genetics Bioscentia MVZ Labor Saar GMBH, Homburg, Germany
| | - Franz Walter
- Radiology Center am Himmelsberg, Zweibrücken, Germany
| | - Frank Lammert
- Department of Medicine II, Saarland University Medical Center, Saarland University, Homburg, Germany; Hannover Medical School (MHH), Germany
| | - Marcin Krawczyk
- Department of Medicine II, Saarland University Medical Center, Saarland University, Homburg, Germany; Laboratory of Metabolic Liver Diseases, Department of General, Transplant and Liver Surgery, Centre for Preclinical Research, Medical University of Warsaw, Poland.
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17
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Sekaran S, Vimalraj S, Thangavelu L. The Physiological and Pathological Role of Tissue Nonspecific Alkaline Phosphatase beyond Mineralization. Biomolecules 2021; 11:1564. [PMID: 34827562 PMCID: PMC8615537 DOI: 10.3390/biom11111564] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/12/2021] [Accepted: 10/12/2021] [Indexed: 12/17/2022] Open
Abstract
Tissue-nonspecific alkaline phosphatase (TNAP) is a key enzyme responsible for skeletal tissue mineralization. It is involved in the dephosphorylation of various physiological substrates, and has vital physiological functions, including extra-skeletal functions, such as neuronal development, detoxification of lipopolysaccharide (LPS), an anti-inflammatory role, bile pH regulation, and the maintenance of the blood brain barrier (BBB). TNAP is also implicated in ectopic pathological calcification of soft tissues, especially the vasculature. Although it is the crucial enzyme in mineralization of skeletal and dental tissues, it is a logical clinical target to attenuate vascular calcification. Various tools and studies have been developed to inhibit its activity to arrest soft tissue mineralization. However, we should not neglect its other physiological functions prior to therapies targeting TNAP. Therefore, a better understanding into the mechanisms mediated by TNAP is needed for minimizing off targeted effects and aid in the betterment of various pathological scenarios. In this review, we have discussed the mechanism of mineralization and functions of TNAP beyond its primary role of hard tissue mineralization.
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Affiliation(s)
- Saravanan Sekaran
- Department of Pharmacology, Saveetha Institute of Medical and Technical Sciences, Saveetha Dental College and Hospitals, Saveetha University, Chennai 600 077, Tamil Nadu, India;
| | - Selvaraj Vimalraj
- Department of Pharmacology, Saveetha Institute of Medical and Technical Sciences, Saveetha Dental College and Hospitals, Saveetha University, Chennai 600 077, Tamil Nadu, India;
- Centre for Biotechnology, Anna University, Chennai 600 025, Tamil Nadu, India
| | - Lakshmi Thangavelu
- Department of Pharmacology, Saveetha Institute of Medical and Technical Sciences, Saveetha Dental College and Hospitals, Saveetha University, Chennai 600 077, Tamil Nadu, India;
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18
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Olander EM, Brunk S, Kesterson J. An Infant with Failure to Thrive and Hypotonia. Neoreviews 2021; 22:e548-e550. [PMID: 34341163 DOI: 10.1542/neo.22-8-e548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Affiliation(s)
- Ellen M Olander
- Department of Pediatrics, University of Columbia-Missouri, Columbia, MO
| | - Samantha Brunk
- Department of Pediatrics, University of Columbia-Missouri, Columbia, MO
| | - Julia Kesterson
- Department of Pediatrics, University of Columbia-Missouri, Columbia, MO
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The Occurrence and Burden of Hypophosphatasia in an Ambulatory Care Endocrinology Practice. Endocr Pract 2021; 27:1189-1192. [PMID: 34265454 DOI: 10.1016/j.eprac.2021.07.005] [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: 04/27/2021] [Revised: 07/02/2021] [Accepted: 07/07/2021] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Hypophosphatasia (HPP) is an inherited disease resulting from loss-of-function mutations in the ALPL gene encoding tissue-nonspecific alkaline phosphatase. The presentation and severity of the disease are highly variable, ranging from perinatal onset with high mortality rates to adult identification with low mortality rates and symptoms ranging from minimal to severe. Moderate forms of HPP typically manifest during middle age and are often undiagnosed. The objective of this study was to determine the occurrence and burden of HPP in an ambulatory care endocrinology practice. METHODS Potential subjects were identified with a computerized text search of patient electronic medical records. Search terms included serum alkaline phosphatase (ALP) levels of ≤40 U/L. Records of patients with at least 2 low ALP levels were reviewed manually to identify potential patients with a history consistent with hypophosphatasia. RESULTS In total, 315 patients with ALP levels ≤40 U/L were identified from an estimated 20 000 patient records. Fifty-six patients with a single low level were excluded from further review. The remaining 259 patients were reviewed, 10 of whom had histories consistent with HPP. None of the identified 10 patients was currently being treated or had previously been treated for HPP. Information about these patients was shared with their respective providers, along with the recommendation to proceed with further evaluation to confirm the diagnosis of HPP. CONCLUSION Hypophosphatasia is an uncommon condition with variable presentation, often resulting in a missed diagnosis. Surveillance of practices by identifying patients with low ALP levels is a rational screening approach to identifying potential patients with HPP.
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20
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Okawa R, Kokomoto K, Nakano K. Dental effects of enzyme replacement therapy in case of childhood-type hypophosphatasia. BMC Oral Health 2021; 21:323. [PMID: 34176466 PMCID: PMC8237502 DOI: 10.1186/s12903-021-01673-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 06/11/2021] [Indexed: 12/02/2022] Open
Abstract
Background Hypophosphatasia (HPP), a skeletal disease characterized by hypomineralization of bone and teeth, is caused by an ALPL gene mutation that leads to low activity of the tissue non-specific alkaline phosphatase enzyme. Although enzyme replacement therapy (ERT) was recently introduced for affected patients, no known studies have been reported regarding its dental effects related to permanent teeth and jaw bones. In the present study, we examined the dental effects of ERT in a case of childhood-type hypophosphatasia, including panoramic radiography findings used to estimate the dental age of permanent teeth and mandibular bone density. Furthermore, the effects of that therapy on the periodontal condition of the patient were evaluated by comparing periodontal pocket depth before and after initiation. Case presentation An 11-year-1-month-old boy was referred to our clinic for consultation regarding oral management. Two primary incisors had spontaneously exfoliated at 1 year 8 months old and he had been diagnosed with childhood-type HPP at the age of 2 years 2 months. Obvious symptoms were localized in the dental region at the time of diagnosis, though later extended to other parts of the body such as bone pain. ERT was started at 11 years 7 months of age, after which bone pain disappeared, and motor functions and activities of daily living improved. We estimated dental age based on tooth development stage. The age gap between chronological and dental ages was expanded before treatment, and then showed a constant decrease after ERT initiation and finally disappeared. The index for mandibular bone density (mandibular cortical width / length from mesial buccal cusp to apex of first molar) was increased after ERT initiation. Furthermore, the periodontal condition for all teeth except those exfoliated was stable after starting therapy. Conclusions ERT resulted in improved tooth and mandibular bone mineralization, with notably good effects on teeth under formation. Acceleration of mineralization of roots associated with erupting teeth leads to stabilization of the periodontal condition. We concluded that ERT contributed to the improved dental condition seen in this patient. Supplementary Information The online version contains supplementary material available at 10.1186/s12903-021-01673-2.
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Affiliation(s)
- Rena Okawa
- Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, 1-8 Yamada-oka, Suita, Osaka, 565-0871, Japan.
| | - Kazuma Kokomoto
- Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, 1-8 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Kazuhiko Nakano
- Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, 1-8 Yamada-oka, Suita, Osaka, 565-0871, Japan
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Fenn JS, Lorde N, Ward JM, Borovickova I. Hypophosphatasia. J Clin Pathol 2021; 74:635-640. [PMID: 33931563 DOI: 10.1136/jclinpath-2021-207426] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 11/04/2022]
Abstract
Hypophosphatasia (HPP) is a group of inherited disorders characterised by the impaired mineralisation of bones and/or teeth and low serum alkaline phosphatase (ALP) activity. It is caused by a mutation in the ALPL gene encoding the tissue-non-specific isoenzyme of ALP (TNSALP) resulting in a loss of function. The disease is highly heterogenous in its clinical expression ranging from stillbirth without mineralised bone to the mild form of late adult onset with symptoms and signs such as musculoskeletal pain, arthropathy, lower-extremity fractures, premature loss of teeth or an incidental finding of reduced serum ALP activity. A classification based on the age at diagnosis and the presence or absence of bone symptoms was historically used: perinatal, prenatal benign, infantile, childhood, adult and odontohypophosphatasia. These subtypes are known to have overlapping signs and complications. Three forms of HPP distinguishable by their genetic characteristics have been described: severe, moderate and mild. Severe forms of HPP (perinatal and infantile severe) are recessively inherited, whereas moderate HPP may be dominantly or recessively inherited. The biochemical hallmark of HPP is persistently low serum ALP for age and increase in natural substrates of TNSALP, pyridoxal 5'-phosphate and phosphoethanolamine supported by radiological findings. The diagnosis is confirmed by ALPL sequencing. A multidisciplinary team of experts is essential for the effective management. Calcium restriction is recommended in infants/children to manage hypercalcaemia. A targeted enzyme replacement therapy for HPP has become available and correct diagnosis is crucial to allow early treatment.
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Affiliation(s)
- Jonathan Samuel Fenn
- Black Country Pathology Services, The Royal Wolverhampton NHS Trust, Wolverhampton, UK
| | - Nathan Lorde
- Department of Clinical Chemistry, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - John Martin Ward
- Department of Radiology, McGill University Health Center, Montreal, Québec, Canada
| | - Ingrid Borovickova
- Department of Biochemical Genetics, Children's Health Ireland at Temple Street, Dublin, Ireland
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22
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TNAP as a New Player in Chronic Inflammatory Conditions and Metabolism. Int J Mol Sci 2021; 22:ijms22020919. [PMID: 33477631 PMCID: PMC7831495 DOI: 10.3390/ijms22020919] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/14/2021] [Accepted: 01/14/2021] [Indexed: 12/19/2022] Open
Abstract
This review summarizes important information on the ectoenzyme tissue-nonspecific alkaline phosphatase (TNAP) and gives a brief insight into the symptoms, diagnostics, and treatment of the rare disease Hypophosphatasia (HPP), which is resulting from mutations in the TNAP encoding ALPL gene. We emphasize the role of TNAP beyond its well-known contribution to mineralization processes. Therefore, above all, the impact of the enzyme on central molecular processes in the nervous system and on inflammation is presented here.
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Ankylosed Primary Molar in a Japanese Child with Hypophosphatasia. Dent J (Basel) 2020; 9:dj9010003. [PMID: 33383819 PMCID: PMC7823531 DOI: 10.3390/dj9010003] [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: 12/07/2020] [Revised: 12/23/2020] [Accepted: 12/24/2020] [Indexed: 12/02/2022] Open
Abstract
Hypophosphatasia (HPP) is a rare genetic disorder; affected patients may experience early exfoliation of primary teeth, especially anterior teeth. However, there have been few reports regarding longitudinal follow-up for primary teeth, especially posterior teeth, until their replacement with permanent teeth. Here, we describe a patient with HPP who underwent follow-up from 1 to 9 years of age. A 14-month-old boy was referred to our hospital with the chief complaint of early loss of primary anterior teeth. He was diagnosed with odonto-type HPP by his pediatrician, due to low serum alkaline phosphatase concentration and early exfoliation of primary teeth with bone hypomineralization. The patient experienced exfoliation of three additional primary anterior teeth by 4 years and 1 month of age. Partial dentures were applied for space maintenance; there were no problems regarding subsequent replacement with permanent teeth in the anterior region. However, the primary mandibular right first molar appeared to be submerged when the patient was 8 years and 3 months of age; the severity of submergence was greater when the patient was 9 years of age. The affected primary molar was considered to be ankylosed; it was extracted when the patient was 9 years and 4 months of age. Histopathological analysis of the tooth revealed disturbed cementum formation, which is a typical characteristic of teeth in patients with HPP. On the basis of these findings, we hypothesize that the disturbed cementum formation could lead to susceptibility to early exfoliation of anterior teeth, as well as occurrence of ankylosis involving posterior teeth.
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Bangura A, Wright L, Shuler T. Hypophosphatasia: Current Literature for Pathophysiology, Clinical Manifestations, Diagnosis, and Treatment. Cureus 2020; 12:e8594. [PMID: 32676235 PMCID: PMC7362651 DOI: 10.7759/cureus.8594] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 06/12/2020] [Indexed: 12/11/2022] Open
Abstract
Hypophosphatasia (HPP) is a rare inherited bone disorder identified by impaired bone mineralization. There are seven subtypes of HPP mainly characterized by their age of onset. These subtypes consist of perinatal (prenatal) benign, perinatal lethal, infantile, childhood, adult, odontohypophosphatasia, and pseudohypophosphatasia. Due to limited awareness of the condition, either misdiagnosis or delayed diagnosis is common. Furthermore, the condition is frequently treated with contraindicated drugs. This literature illustrates the most recent findings on the etiology, pathophysiology, clinical manifestations, diagnosing, and treatment for HPP and its subtypes. The etiology of the disease consists of loss-of-function mutations of the ALPL gene on chromosome one, which encodes for tissue nonspecific isoenzyme of alkaline phosphatase (TNAP). A decrease of TNAP reduces inorganic phosphate (Pi) for bone mineralization and allows for an increase in inorganic pyrophosphate (PPi) and phosphorylated osteopontin (p-OPN), which further reduces bone mineralization. The combination of these processes softens bone and mediates a clinical presentation similar to rickets/osteomalacia. HPP has an additional wide range of clinical features depending on its subtype. Although a concrete diagnostic guideline has not yet been established, many studies have supported a similar method of identifying HPP. Clinical features, radiological findings, and/or biomarker levels of the disorder should raise suspicion and encourage the inclusion of HPP as a differential diagnosis. Biomarkers, especially alkaline phosphatase (ALP), are major contributors to diagnosis. However, genetic testing is done for definitive diagnosis. The primary treatment for HPP is the reintroduction of TNAP as a recombinant enzyme called asfotase alfa. There are additional pharmaceutical treatments and in some cases, surgical intervention may be indicated. Pharmaceutical therapies such as bisphosphonates, denosumab, potent antiresorptive agents, and vitamin D are contraindicated in adults with HPP. We hope to raise awareness for HPP in order to prevent delayed diagnosis or misdiagnosis. We plan to encourage appropriate care and avoid treatments that may be contraindicating. We also encourage the development of a diagnostic guideline that will promote a consistently favorable patient prognosis.
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Affiliation(s)
- Abdulai Bangura
- Department of Research, Trinity School of Medicine, Ratho Mill, VCT
| | - Lisa Wright
- Department of Orthopaedics, Carilion Clinic, Roanoke, USA
| | - Thomas Shuler
- Department of Orthopaedics, Carilion Clinic, Roanoke, USA
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Fujisawa Y, Kitaoka T, Ono H, Nakashima S, Ozono K, Ogata T. Case Report: Efficacy of Reduced Doses of Asfotase Alfa Replacement Therapy in an Infant With Hypophosphatasia Who Lacked Severe Clinical Symptoms. Front Endocrinol (Lausanne) 2020; 11:590455. [PMID: 33391183 PMCID: PMC7775725 DOI: 10.3389/fendo.2020.590455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 11/12/2020] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Hypophosphatasia is a rare bone disease characterized by impaired bone mineralization and low alkaline phosphatase activity. Here, we describe the course of bone-targeted enzyme replacement therapy with asfotase alpha for a female infant patient with hypophosphatasia who lacked apparent severe clinical symptoms. CASE PRESENTATION The patient exhibited low serum alkaline phosphatase (60 U/L; age-matched reference range, 520-1,580) in a routine laboratory test at birth. Further examinations revealed skeletal demineralization and rachitic changes, as well as elevated levels of serum calcium (2.80 mmol/L; reference range, 2.25-2.75 mmol/L) and ionic phosphate (3.17 mmol/L; reference range, 1.62-2.48 mmol/L), which are typical features in patients with hypophosphatasia. Sequencing analysis of the tissue-nonspecific alkaline phosphatase (TNSALP) gene identified two pathogenic mutations: c.406C>T, p.Arg136Cys and c.979T>C, p.Phe327Leu. Thus, the patient was diagnosed with hypophosphatasia. At the age of 37 days, she began enzyme replacement therapy using asfotase alpha at the standard dose of 6 mg/kg/week. Initial therapy from the age of 37 days to the age of 58 days substantially improved rickets signs in the patient; it also provided immediate normalization of serum calcium and ionic phosphate levels. However, serum ionic phosphate returned to a high level (2.72 mmol/L), which was presumed to be a side effect of asfotase alpha. Thus, the patient's asfotase alfa treatment was reduced to 2 mg/kg/week, which allowed her to maintain normal or near normal skeletal features thereafter, along with lowered serum ionic phosphate levels. Because the patient exhibited slight distal metaphyseal demineralization in the knee at the age of 2 years and 6 months, her asfotase alfa treatment was increased to 2.4 mg/kg/week. No signs of deterioration in bone mineralization were observed thereafter. At the age of 3 years, the patient's motor and psychological development both appeared normal, compared with children of similar age. CONCLUSION This is the first report in which reduced doses of asfotase alfa were administered to an infant patient with hypophosphatasia who lacked apparent severe clinical symptoms. The results demonstrate the potential feasibility of a tailored therapeutic option based on clinical severity in patients with hypophosphatasia.
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Affiliation(s)
- Yasuko Fujisawa
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
- *Correspondence: Yasuko Fujisawa,
| | - Taichi Kitaoka
- Department of Pediatrics, Faculty of Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Hiroyuki Ono
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Shinichi Nakashima
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Keiichi Ozono
- Department of Pediatrics, Faculty of Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Tsutomu Ogata
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
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