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Tasevski S, Kyung Nam H, Ghannam A, Moughni S, Atoui T, Mashal Y, Hatch N, Zhang Z. Tissue nonspecific alkaline phosphatase deficiency impairs Purkinje cell development and survival in a mouse model of infantile hypophosphatasia. Neuroscience 2024; 560:357-370. [PMID: 39369942 DOI: 10.1016/j.neuroscience.2024.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2024] [Revised: 09/26/2024] [Accepted: 10/02/2024] [Indexed: 10/08/2024]
Abstract
Loss-of-function mutations in the tissue-nonspecific alkaline phosphatase (TNAP) gene can result in hypophosphatasia (HPP), an inherited multi-systemic metabolic disorder that is well-known for skeletal and dental hypomineralization. However, emerging evidence shows that both adult and pediatric patients with HPP suffer from cognitive deficits, higher measures of depression and anxiety, and impaired sensorimotor skills. The cerebellum plays an important role in sensorimotor coordination, cognition, and emotion. To date, the impact of TNAP mutation on the cerebellar circuitry development and function remains poorly understood. The main objective of this study was to investigate the roles of TNAP in cerebellar development and function, with a particular focus on Purkinje cells, in a mouse model of infantile HPP. Male and female wild type (WT) and TNAP knockout (KO) mice underwent behavioral testing on postnatal day 13-14 and were euthanized after completion of behavioral tests. Cerebellar tissues were harvested for gene expression and immunohistochemistry analyses. We found that TNAP mutation resulted in significantly reduced body weight, shorter body length, and impaired sensorimotor functions in both male and female KO mice. These developmental and behavioral deficits were accompanied by abnormal Purkinje cell morphology and dysregulation of genes that regulates synaptic transmission, cellular growth, proliferation, and death. In conclusion, inactivation of TNAP via gene deletion causes developmental delays, sensorimotor impairment, and Purkinje cell maldevelopment. These results shed light on a new perspective of cerebellar dysfunction in HPP.
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Affiliation(s)
- Stefanie Tasevski
- Department of Natural Sciences, College of Arts, Sciences, and Letters, University of Michigan-Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128, USA
| | - Hwa Kyung Nam
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan-Ann Arbor, 1011 N University Ave, Ann Arbor, MI 48109, USA
| | - Amanda Ghannam
- Department of Natural Sciences, College of Arts, Sciences, and Letters, University of Michigan-Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128, USA
| | - Sara Moughni
- Department of Natural Sciences, College of Arts, Sciences, and Letters, University of Michigan-Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128, USA
| | - Tia Atoui
- Department of Natural Sciences, College of Arts, Sciences, and Letters, University of Michigan-Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128, USA
| | - Yara Mashal
- Department of Natural Sciences, College of Arts, Sciences, and Letters, University of Michigan-Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128, USA
| | - Nan Hatch
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan-Ann Arbor, 1011 N University Ave, Ann Arbor, MI 48109, USA
| | - Zhi Zhang
- Department of Natural Sciences, College of Arts, Sciences, and Letters, University of Michigan-Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128, USA.
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Dahir KM, Rush ET, Diaz-Mendoza S, Kishnani PS. A Delphi panel to build consensus on assessing disease severity and disease progression in adult patients with hypophosphatasia in the United States. J Endocrinol Invest 2024; 47:1487-1497. [PMID: 38236379 PMCID: PMC11142979 DOI: 10.1007/s40618-023-02256-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 11/21/2023] [Indexed: 01/19/2024]
Abstract
BACKGROUND Hypophosphatasia (HPP) is an inborn error of metabolism with a variable presentation. We conducted a modified Delphi panel to obtain expert consensus on knowledge gaps regarding disease severity and progression in adult patients with HPP. METHODS Healthcare professionals (HCPs) with experience managing adult patients with HPP were recruited to participate in a 3-round Delphi panel (round 1: paper survey and 1:1 interview; rounds 2-3: email survey). Panelists rated the extent of their agreement with statements about disease severity and progression in adult patients with HPP. Consensus was defined as ≥ 80% agreement. RESULTS Ten HCPs completed round 1; nine completed rounds 2 and 3. Consensus was reached on 46/120 statements derived from steering committee input. Disease severity markers in adult patients with HPP can be bone-related (recurrent/poorly healing fractures, pseudo-fractures, metatarsal fractures, osteomalacia) or involve dentition or physiologic/functional manifestations (use of mobility devices/home modifications, abnormal gait, pain). Disease progression markers can include recurrent/poorly healing low-trauma fractures, development of ectopic calcifications, and/or impairment of functional activity. Panelists supported the development of a tool to help assess disease severity in the clinic and track changes in severity over time. Panelists also highlighted the role of a multidisciplinary team, centers with expertise, and the need to refer patients when disease severity is not clear. CONCLUSIONS These statements regarding disease severity, progression, and assessment methods address some knowledge gaps in adult patients with HPP and may be helpful for treating HCPs, although the small sample size affects the ability to generalize the healthcare provider experience.
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Affiliation(s)
- K M Dahir
- Division of Endocrinology and Metabolism, Vanderbilt University Medical Center, 1215 21st Ave S Suite 8210, Nashville, TN, 37232, USA.
| | - E T Rush
- Division of Clinical Genetics, Children's Mercy Kansas City, 2401 Gillham Rd, Kansas City, MO, 64108, USA.
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, MO, USA.
- Department of Internal Medicine, University of Kansas School of Medicine, Kansas City, KS, USA.
| | | | - P S Kishnani
- Division of Medical Genetics, Department of Pediatrics, Duke University School of Medicine, Durham, NC, USA
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Högler W, Linglart A, Petryk A, Kishnani PS, Seefried L, Fang S, Rockman-Greenberg C, Ozono K, Dahir K, Martos-Moreno GÁ. Growth and disease burden in children with hypophosphatasia. Endocr Connect 2023; 12:e220240. [PMID: 36917043 PMCID: PMC10160547 DOI: 10.1530/ec-22-0240] [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: 02/16/2023] [Accepted: 03/14/2023] [Indexed: 03/15/2023]
Abstract
Objective Hypophosphatasia, an inborn error of metabolism characterized by impaired bone mineralization, can affect growth. This study evaluated relationships between anthropometric parameters (height, weight, and body mass index) and clinical manifestations of hypophosphatasia in children. Design Data from children (aged <18 years) with hypophosphatasia were analyzed from the observational Global Hypophosphatasia Registry. Methods Anthropometric parameters were evaluated by age group (<2 years and ≥2 years) at assessment. The frequency of hypophosphatasia manifestations was compared between children with short stature (< percentile) and those with normal stature. Results This analysis included 215 children (54.4% girls). Short stature presented in 16.1% of children aged <2 years and 20.4% of those aged ≥2 years at assessment. Among those with available data (n = 62), height was below the target height (mean: -0.66 standard deviations). Substantial worsening of growth (mean delta height z score: -1.45; delta weight z score: -0.68) occurred before 2 years of age, while in those aged ≥2 years, anthropometric trajectories were maintained (delta height z score: 0.08; delta weight z score: 0.13). Broad-ranging hypophosphatasia manifestations (beyond dental) were observed in most children. Conclusions Short stature was not a consistent characteristic of children with hypophosphatasia, but growth impairment was observed in those aged <2 years, indicating that hypophosphatasia might affect growth plate activity during infancy. In addition, a broad range of clinical manifestations occurred in those above and below the third percentile for height, suggesting that height alone may not accurately reflect hypophosphatasia disease burden and that weight is less affected than longitudinal growth.
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Affiliation(s)
- Wolfgang Högler
- Department of Paediatrics and Adolescent Medicine, Johannes Kepler University Linz, Linz, Austria
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Agnès Linglart
- AP-HP, Hôpital Bicêtre Paris Saclay, service d’endocrinologie et diabète de l’enfant, DMU 3 SEA, centre de référence des maladies rares du métabolisme du calcium et du phosphate, filière OSCAR; Université de Paris-Saclay INSERM U1185, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Anna Petryk
- Alexion, AstraZeneca Rare Disease, Boston, Massachusetts, USA
| | | | | | - Shona Fang
- Alexion, AstraZeneca Rare Disease, Boston, Massachusetts, USA
| | | | | | - Kathryn Dahir
- Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Gabriel Ángel Martos-Moreno
- Departments of Pediatrics and Pediatric Endocrinology Hospital Infantil Universitario Niño Jesús, IIS La Princesa, Universidad Autónoma de Madrid, CIBERobn, ISCIII, Madrid, Spain
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Semler O, Partsch CJ, Das AM, Prechtl A, Grasemann C. Cross-sectional analysis: clinical presentation of children with persistently low ALP levels. J Pediatr Endocrinol Metab 2021; 34:1559-1566. [PMID: 34428361 DOI: 10.1515/jpem-2021-0330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 08/06/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Low activity of serum alkaline phosphatase (ALP) is a hallmark of hypophosphatasia (HPP), but low readings of ALP are not always recognized in clinical routine. Understanding the clinical presentations associated with low ALP may contribute to a timelier diagnosis of HPP. METHODS Data from paediatric patients with low ALP, excluding patients in intensive care and with oncological/haematological disorders, were analysed. Most recent ALP values, previous diagnoses, medication and relevant symptoms were extracted from patient records at nine specialised centres and analysed descriptively. A relationship between body height and ALP values was scrutinised by linear regression. RESULTS Of 370 children, 15 (4.1%) had a diagnosis of HPP. In the subgroup without a diagnosis of HPP, 241 (67.9%) out of 355 patients had one or more medical conditions known to be associated with low serum ALP. Of those, hypothyroidism, malnutrition and steroid administration were most frequent. Characteristic symptoms, particularly, short stature, muscle weakness and delay of motor development were more frequent and ALP values were lower in patients with documented HPP diagnosis compared to patients without diagnosis of HPP (Ø z-scores: -2.52) (interquartile range [IQR] = 0.20) vs. -1.96 (IQR = 0.87). A weak positive linear relationship between z-scores of ALP and body height was identified (p<0.001). CONCLUSIONS This analysis of paediatric patient records elucidates a wide range of disorders associated with low ALP activity. In case of additional specific symptoms, HPP should always be considered as a differential diagnosis.
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Affiliation(s)
- Oliver Semler
- Centre for Rare Skeletal Diseases in childhood, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.,Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | | | - Anibh Martin Das
- Department of Paediatrics, Hannover Medical School, Hannover, Germany.,Centre for Rare Diseases, Hannover Medical School, Centre for Systems Neurosciences, Hannover, Germany
| | | | - Corinna Grasemann
- Department of Pediatrics, Division of Rare Diseases, St. Josef-Hospital, Ruhr-University Bochum, Bochum, Germany
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Stürznickel J, Schmidt FN, von Vopelius E, Delsmann MM, Schmidt C, Jandl NM, Oheim R, Barvencik F. Bone healing and reactivation of remodeling under asfotase alfa therapy in adult patients with pediatric-onset hypophosphatasia. Bone 2021; 143:115794. [PMID: 33301963 DOI: 10.1016/j.bone.2020.115794] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/16/2020] [Accepted: 12/03/2020] [Indexed: 01/13/2023]
Abstract
Hypophosphatasia (HPP) is a hereditary musculoskeletal disorder caused by inactivating variants in the ALPL gene and subsequently reduced serum tissue-nonspecific alkaline phosphatase (TNSALP) activity. This inborn error of metabolism results in decreased bone quality, accumulations of osteoid, and reduced bone mineralization. Increased incidence of fractures and prolonged bone healing are characteristic features for HPP. Available enzyme replacement therapy (asfotase alfa), was reported to recover bone mineralization and bone quality in adult HPP patients. Moreover, it was shown that asfotase alfa improved fracture healing of former nonunions in two adult HPP patients. We hypothesized that the nonunions are filled partially with osteoid, offering great potential to benefit from the treatment with asfotase alfa to promote bone healing. In the present study, we report three adult patients with pediatric-onset HPP and detected ALPL-mutations with prolonged bone healing after arthrodesis, tibial stress fracture, and osteotomy. After the initiation of asfotase alfa, immediately increased levels of alkaline phosphatase (ALP) and bone-specific ALP, as well as decreased levels of pyridoxal-5-phosphate (PLP), were detected in biochemical analysis. Importantly, even after up to 5 years of non-healing, a progredient consolidation was shown, assessed by a custom three-dimensional evaluation of repeated cone-beam computed tomography (CBCT) images, characterized by rapidly increasing levels of bone volume per tissue volume (BV/TV) within the volume of interest (i.e., the region of the non-healing bone). These radiographical findings were in line with the reported restoration of functional ability and pain-free full weight-bearing, as well as increased neuromuscular parameters (e.g., improved muscle strength). Taken together, our findings indicate that asfotase alfa improves the osseous consolidation of nonunions likely due to re-mineralization of osteoid tissue filling the former gap and improving the functional ability in adult HPP patients, characterized by increasing levels of BV/TV assessed via an innovative three-dimensional evaluation of CBCT images.
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Affiliation(s)
- Julian Stürznickel
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Felix N Schmidt
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Emil von Vopelius
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Maximilian M Delsmann
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Constantin Schmidt
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nico Maximilian Jandl
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ralf Oheim
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Martin Zeitz Center for Rare Diseases, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Florian Barvencik
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Martin Zeitz Center for Rare Diseases, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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Kramer K, Chavez MB, Tran AT, Farah F, Tan MH, Kolli TN, Dos Santos EJL, Wimer HF, Millán JL, Suva LJ, Gaddy D, Foster BL. Dental defects in the primary dentition associated with hypophosphatasia from biallelic ALPL mutations. Bone 2021; 143:115732. [PMID: 33160095 PMCID: PMC7769999 DOI: 10.1016/j.bone.2020.115732] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 10/29/2020] [Accepted: 11/02/2020] [Indexed: 12/12/2022]
Abstract
ALPL encodes tissue-nonspecific alkaline phosphatase (TNAP), an enzyme expressed in bone, teeth, liver, and kidney. ALPL loss-of-function mutations cause hypophosphatasia (HPP), an inborn error-of-metabolism that produces skeletal and dental mineralization defects. Case reports describe widely varying dental phenotypes, making it unclear how HPP comparatively affects the three unique dental mineralized tissues: enamel, dentin, and cementum. We hypothesized that HPP affected all dental mineralized tissues and aimed to establish quantitative measurements of dental tissues in a subject with HPP. The female proband was diagnosed with HPP during childhood based on reduced alkaline phosphatase activity (ALP), mild rachitic skeletal effects, and premature primary tooth loss. The diagnosis was subsequently confirmed genetically by the presence of compound heterozygous ALPL mutations (exon 5: c.346G>A, p.A116T; exon 10: c.1077C>G, p.I359M). Dental defects in 8 prematurely exfoliated primary teeth were analyzed by high resolution micro-computed tomography (micro-CT) and histology. Similarities to the Alpl-/- mouse model of HPP were identified by additional analyses of murine dentoalveolar tissues. Primary teeth from the proband exhibited substantial remaining root structure compared to healthy control teeth. Enamel and dentin densities were not adversely affected in HPP vs. control teeth. However, analysis of discrete dentin regions revealed an approximate 10% reduction in the density of outer mantle dentin of HPP vs. control teeth. All 4 incisors and the molar lacked acellular cementum by micro-CT and histology, but surprisingly, 2 of 3 prematurely exfoliated canines exhibited apparently normal acellular cementum. Based on dentin findings in the proband's teeth, we examined dentoalveolar tissues in a mouse model of HPP, revealing that the delayed initiation of mineralization in the incisor mantle dentin was associated with a broader lack of circumpulpal dentin mineralization. This study describes a quantitative approach to measure effects of HPP on dental tissues. This approach has uncovered a previously unrecognized novel mantle dentin defect in HPP, as well as a surprising and variable cementum phenotype within the teeth from the same HPP subject.
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Affiliation(s)
- K Kramer
- Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - M B Chavez
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - A T Tran
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - F Farah
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - M H Tan
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - T N Kolli
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - E J Lira Dos Santos
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA; Department of Prosthodontics and Periodontics, Division of Periodontics, Piracicaba Dental School, University of Campinas-UNICAMP, Piracicaba, SP, Brazil
| | - H F Wimer
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA; National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - J L Millán
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - L J Suva
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - D Gaddy
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - B L Foster
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA.
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