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Salama M, Al Nofal A, Tebben P. Severe Hypercalcemia Associated With Perinatal Hypophosphatasia While Receiving Enzyme Replacement Therapy. JCEM CASE REPORTS 2025; 3:luaf066. [PMID: 40236614 PMCID: PMC11997545 DOI: 10.1210/jcemcr/luaf066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2024] [Indexed: 04/17/2025]
Abstract
Hypophosphatasia (HPP) is characterized by defective bone mineralization due to reduced function of tissue-nonspecific alkaline phosphatase (TNSALP) caused by pathogenic ALPL gene variants. Hypercalcemia is more common in the perinatal and infantile forms and may be mitigated or prevented with enzyme replacement therapy asfotase alfa (AA). Here, we report a patient who developed severe hypercalcemia while receiving AA. Hypercalcemia was initially managed with intravenous fluids, dietary calcium restriction, and maximizing AA dose. Despite these measures, she required an additional hospital admission, at which time calcitonin 4 IU/kg every 12 hours was initiated. On this regimen, her calcium normalized without recurrence of severe hypercalcemia. Over the subsequent 8 months, restrictions of calcium intake were slowly lifted, and calcitonin was tapered and discontinued with maintenance of calcium within the normal range. This case underscores the significance of vigilant monitoring of calcium levels and dietary intake in infants diagnosed with HPP. While calcitonin is typically not considered as a sustained treatment for hypercalcemia, the present case illustrates the efficacy of adjunct calcitonin therapy, in conjunction with restricted calcium intake and maximum AA dosing, in managing severe hypercalcemia in an infant with perinatal HPP.
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Affiliation(s)
- Mostafa Salama
- Division of Pediatric Endocrinology and Metabolism, Mayo Clinic, Rochester, MN 55905, USA
| | - Alaa Al Nofal
- Division of Pediatric Endocrinology and Metabolism, Mayo Clinic, Rochester, MN 55905, USA
| | - Peter Tebben
- Division of Pediatric Endocrinology and Metabolism, Mayo Clinic, Rochester, MN 55905, USA
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Akiyama T, Kubota T, Murayama K, Fujiwara M, Ohata Y, Ozono K, Tajika M, Ichimoto K, Sugiyama Y, Akiyama M, Shibata T, Tsuchiya H. Vitamin B6 Status in Hypophosphatasia: Association With Clinical Severity, Diagnostic Utility, and Effects on Vitamin B6 Metabolism by Supplementation and Enzyme Replacement Therapy. J Inherit Metab Dis 2025; 48:e70036. [PMID: 40387451 DOI: 10.1002/jimd.70036] [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: 12/29/2024] [Revised: 04/03/2025] [Accepted: 04/22/2025] [Indexed: 05/20/2025]
Abstract
This study reports the concentrations of major vitamin B6 (VB6) vitamers (pyridoxal 5'-phospate [PLP], pyridoxal [PL], and 4-pyridoxic acid [PA]) in over 100 hypophosphatasia (HPP) cases to explore clues for clinical severity, to improve diagnostic sensitivity, and to examine VB6 changes by supplementation and enzyme replacement therapy. Serum samples were collected from HPP and non-HPP patients. When available, cerebrospinal fluid (CSF) samples were also analyzed to determine PLP, PL, and PA concentrations. Serum PLP concentrations, PLP-to-PL ratios, and PLP-to-PA ratios were higher in untreated HPP patients compared to non-HPP patients and reflected clinical severity. Perinatal severe HPP showed lower PL concentrations than perinatal benign HPP and the lowest PA concentrations among all clinical forms. Combining PLP-to-PL ratios with PLP concentrations improved diagnostic sensitivity. Under VB6 therapy, PLP concentrations and PLP-to-PL ratios remained higher in HPP patients than in non-HPP patients. VB6 changes produced by ERT were most clearly reflected by the reduction of PLP-to-PL ratios. CSF PLP concentrations and PLP-to-PL ratios were higher in untreated HPP patients than in non-HPP patients, while CSF PL concentrations were higher in patients on ERT compared to those not on ERT. Co-evaluation of serum PLP, PL, and PA concentrations may help understand clinical severity, can improve diagnostic sensitivity, and can demonstrate the effect of ERT on VB6 metabolism more effectively than the assay of PLP concentrations alone. Altered VB6 status in the CSF suggests that tissue-nonspecific alkaline phosphatase plays a key role in VB6 transport from peripheral blood to the brain via the blood-CSF barrier.
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Affiliation(s)
- Tomoyuki Akiyama
- Department of Pediatric Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Takuo Kubota
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Kei Murayama
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
- Department of Pediatrics, Juntendo University Faculty of Medicine, Tokyo, Japan
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Makoto Fujiwara
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yasuhisa Ohata
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Keiichi Ozono
- Center for Promoting Treatment of Intractable Diseases, ISEIKAI International General Hospital, Osaka, Japan
| | - Makiko Tajika
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Keiko Ichimoto
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Yohei Sugiyama
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
- Department of Pediatrics, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Mari Akiyama
- Department of Pediatric Neurology, Okayama University Hospital, Okayama, Japan
| | - Takashi Shibata
- Department of Pediatric Neurology, Okayama University Hospital, Okayama, Japan
| | - Hiroki Tsuchiya
- Department of Pediatric Neurology, Okayama University Hospital, Okayama, Japan
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Kanno J, Nakagawa T, Miura A, Shima H, Sogi C, Kamimura M, Fujiwara I, Tachikawa K, Hino R, Michigami T, Kikuchi A. Effects of enzyme replacement therapy in sibling cases of hypophosphatasia of varying severities. Clin Pediatr Endocrinol 2025; 34:137-143. [PMID: 40201376 PMCID: PMC11972865 DOI: 10.1297/cpe.2024-0084] [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: 11/01/2024] [Accepted: 01/17/2025] [Indexed: 04/10/2025] Open
Abstract
Hypophosphatasia (HPP) is a hereditary disorder characterized by impaired bone mineralization caused by decreased tissue-nonspecific alkaline phosphatase (TNSALP) activity. Specifically, HPP is caused by a loss-of-function variant in the ALPL gene encoding TNSALP. Although genotype-phenotype correlations have been described, phenotypic differences have been reported in patients with the same variants, even within families. The proband, a girl, was suspected to have in utero fractures of the long bones, suggestive of osteogenesis imperfecta. No respiratory impairment was observed after birth; however, the patient's serum alkaline phosphatase level was low. In addition, the patient's perinatal findings were consistent with those of perinatal benign HPP, although the bone symptoms subsequently worsened. The patient's brother, initially suspected to have odonto-HPP due to the premature loss of primary teeth, later developed compression fractures and extraosseous symptoms. Both patients had the same ALPL variants, c. 572A>G(;)1559del, p. Glu191Gly(;)Leu520ArgfsTer86; however, the severity of their conditions differed. Patients with HPP with identical genotypes in the same family may have varying severity levels of HPP. In this case report, both patients received enzyme replacement therapy (ERT), which improved the clinical symptoms. Therefore, for perinatal benign HPP, ERT should be considered if bone symptoms worsen. In addition, odonto-HPP should be closely monitored, and ERT should be considered if bone and extraosseous symptoms arise.
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Affiliation(s)
- Junko Kanno
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Tomohiro Nakagawa
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Akinobu Miura
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Hirohito Shima
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Chisumi Sogi
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Pediatrics, Japan Community Health Care Organization Sendai Hospital, Sendai, Japan
| | - Miki Kamimura
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Pediatrics, National Hospital Organization Sendai Medical Center, Sendai, Japan
| | - Ikuma Fujiwara
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Pediatrics, Sendai City Hospital, Sendai, Japan
| | - Kanako Tachikawa
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka Prefectural Hospital Organization, Izumi, Japan
| | - Ryoko Hino
- Division of Pediatric Dentistry, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Toshimi Michigami
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka Prefectural Hospital Organization, Izumi, Japan
| | - Atsuo Kikuchi
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Sendai, Japan
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Rush ET, Del Angel G, Dong J, Bates T, Steiner RD, Cox A. Genetic characterization of a large cohort of individuals with a clinical suspicion of hypophosphatasia in the United States. Mol Genet Metab 2025; 144:109046. [PMID: 39983296 DOI: 10.1016/j.ymgme.2025.109046] [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: 12/03/2024] [Revised: 01/22/2025] [Accepted: 01/29/2025] [Indexed: 02/23/2025]
Abstract
Hypophosphatasia (HPP) is a rare metabolic disease resulting from variants in ALPL, inherited in an either autosomal recessive or autosomal dominant manner. Sponsored clinical ALPL testing was offered in the US for individuals with a clinical suspicion of HPP. Gene variants were assessed to determine the likelihood of identifying disease-causing variants, uncover genotype-phenotype relationships, and for further understanding of ALPL variants in the US HPP population. Variants were detected by Sanger sequencing and classified as pathogenic or likely pathogenic (P/LP; positive test result), variant(s) of uncertain significance (indeterminate test result), benign or likely benign (negative test result), or no variants (negative test result). Clinical signs/symptoms, age, sex, and family history data were voluntarily reported by participating clinicians and were explored for possible association with the test result. Of 1103 individuals tested, results were positive in 40 %, indeterminate in 5 %, and negative in 55 %. Most positive tests were monoallelic P/LP variants (n = 413). The most frequently identified P/LP variants were c.1133A > T/p.Asp378Val (n = 61), c.571G > A/p.Glu191Lys (n = 47), and c.1250A > G/p.Asn417Ser (n = 44). In total, 23 novel ALPL variants were identified, of which 43 % were P/LP and the most frequent type was missense (74 %). Among the 25 % of participants for whom signs/symptoms were reported, a significant association was observed for those with a family history of HPP signs/symptoms and a positive test result. These data contribute important information on the likelihood of disease-causing ALPL variants in individuals with clinical signs/symptoms of HPP, the importance of family history in HPP testing, distribution of ALPL variants, and identification of novel ALPL variants.
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Affiliation(s)
| | - Guillermo Del Angel
- Centre for Genomics Research, Discovery Sciences, Biopharmaceuticals R&D, AstraZeneca, Boston, MA, USA.
| | - Juan Dong
- PreventionGenetics, part of Exact Sciences, Marshfield, WI, USA.
| | - Toby Bates
- Alexion, AstraZeneca Rare Disease, Boston, MA, USA.
| | - Robert D Steiner
- PreventionGenetics, part of Exact Sciences, Marshfield, WI, USA; University of Wisconsin-Madison, Madison, WI, USA.
| | - Allison Cox
- PreventionGenetics, part of Exact Sciences, Marshfield, WI, USA; University of Rochester Medical Center, Rochester, NY, USA.
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Dhananjaya MS, Thrupti S, Reddy HV, Nadig A, Adarsh KS, Jadhav S, Lalitha P, Nair S, Bhattacharyya S, Lila A, Sarathi V. Phenotypic and Genotypic Spectrum of Indian Patients with Hypophosphatasia. Indian J Endocrinol Metab 2025; 29:188-194. [PMID: 40416455 PMCID: PMC12101758 DOI: 10.4103/ijem.ijem_378_24] [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: 09/18/2024] [Revised: 12/28/2024] [Accepted: 01/10/2025] [Indexed: 05/27/2025] Open
Abstract
Introduction Hypophosphatasia (HPP) is a rare disorder, with only two genetically proven cases reported from India. Here, We report five Indian patients with genetically proven hypophosphatasia and describe their clinical, biochemical, and genetic profiles. Methods The study included patients with genetically proven hypophosphatasia managed at different healthcare centers in South India. The participants' case records were reviewed, and relevant phenotypic and genotypic information was collected and analyzed. Results Case 1 presented at 4 months of age for failure to thrive, found to have persistent hypercalcemia for which she received bisphosphonate therapy. A low alkaline phosphatase was recognized later. Case 2 presented during adolescence with bilateral genu valgus and delayed dentition with classical tongue-like translucencies on radiology and low alkaline phosphatase. Genetic evaluation in cases 1 and 2 revealed compound heterozygous variants in the ALPL gene. Case 1 received asfotase alfa with remarkable improvement in growth. Case 3 presented with multiple vertebral fractures at 33 years of age whereas cases 4 (42 years) and 5 (63 years) presented with musculoskeletal pains with delayed diagnosis for 8 and 13 years, respectively. Cases 3-5 had heterozygous variants in the ALPL gene. Conclusions In the largest case series of hypophosphatasia from India, we report five cases of hypophosphatasia with two novel variants. Our study emphasizes the need to increase awareness regarding the disease to improve its early diagnosis and also, the need to form strategies to reduce the challenges in obtaining enzyme replacement therapy for hypophosphatasia in India.
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Affiliation(s)
- Melkunte S. Dhananjaya
- Department of Endocrinology, Vydehi Institute of Medical Sciences and Research Center, Bengaluru, Karnataka, India
| | - S. Thrupti
- Kangaroo Care Hospitals, Mysore, Karnataka, India
| | - Hamsa V. Reddy
- Department of Pediatrics, Division of Pediatric Nephrology, M S Ramaiah Medical College, Bengaluru, Karnataka, India
| | - Anusha Nadig
- Department of Endocrinology, Vydehi Institute of Medical Sciences and Research Center, Bengaluru, Karnataka, India
| | | | - Swati Jadhav
- Department of Endocrinology, Vydehi Institute of Medical Sciences and Research Center, Bengaluru, Karnataka, India
| | | | - Sandhya Nair
- Senior Manager - Variant Interpretation, MedGenome Labs Ltd, Bengaluru, Karnataka, India
| | | | - Anurag Lila
- Department of Endocrinology, Seth Gordhandas Sunderdas Medical College and King Edward Memorial Hospital, Mumbai, Maharashtra, India
| | - Vijaya Sarathi
- Department of Endocrinology, Vydehi Institute of Medical Sciences and Research Center, Bengaluru, Karnataka, India
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Noda Y, Kido J, Sawada T, Tanaka K, Kumeda K, Yoshida S, Sugawara K, Nakamura K. Newborn screening for hypophosphatasia: development of a high-throughput tissue nonspecific alkaline phosphatase activity assay using dried blood spots. JBMR Plus 2025; 9:ziae172. [PMID: 39925621 PMCID: PMC11803525 DOI: 10.1093/jbmrpl/ziae172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2024] [Revised: 12/11/2024] [Accepted: 12/24/2024] [Indexed: 02/11/2025] Open
Abstract
Hypophosphatasia (HPP) is an inherited metabolic disease caused by deficiency of tissue nonspecific alkaline phosphatase (TNAP) caused by pathogenic variants of the ALPL gene (MIM 171760). The clinical manifestations of HPP vary, ranging from a lethal perinatal-onset type to a moderate late-onset type presenting with nonspecific symptoms, such as arthropathy and musculoskeletal pain. HPP is characterized by low TNAP activity and defective bone mineralization, leading to bone deformity and skeletal abnormalities. Moreover, this disease can cause systemic complications, such as muscle weakness, seizures, pain, and respiratory failure, leading to premature death in infants. This study aimed to evaluate whether measuring TNAP activity in dried blood spots (DBSs) can identify patients with HPP. We developed an assay to assess TNAP activity using DBSs and screened 45 632 newborns born between February 2019 and March 2022 in Kumamoto Prefecture in Japan for HPP. We detected a single heterozygous variant of the ALPL gene in 5 newborns. During the clinical course follow-up, one newborn presented with HPP-related clinical manifestations. This is the first study on newborn screening (NBS) for HPP worldwide. NBS for HPP using DBSs may be practical and beneficial, as it is a high-throughput method. Moreover, the DBSs used for the TNAP assay are the same as those used for public-funded NBS worldwide. In the future, this system may be implemented as standard NBS for HPP.
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Affiliation(s)
- Yusuke Noda
- Department of Pediatrics, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
- Department of Pediatrics, Kumamoto University Hospital, Kumamoto, Japan
| | - Jun Kido
- Department of Pediatrics, Kumamoto University Hospital, Kumamoto, Japan
- Department of Pediatrics, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Takaaki Sawada
- Department of Pediatrics, Kumamoto University Hospital, Kumamoto, Japan
- Department of Pediatrics, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Kenichi Tanaka
- Department of Pediatrics, Kumamoto University Hospital, Kumamoto, Japan
| | | | | | - Keishin Sugawara
- Department of Pediatrics, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Kimitoshi Nakamura
- Department of Pediatrics, Kumamoto University Hospital, Kumamoto, Japan
- Department of Pediatrics, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
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Moro L. A case study of hypophosphatasia: An underdiagnosed bone disorder characterized by low alkaline phosphatase. J Am Assoc Nurse Pract 2025; 37:189-195. [PMID: 39591362 DOI: 10.1097/jxx.0000000000001099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Accepted: 10/29/2024] [Indexed: 11/28/2024]
Abstract
ABSTRACT Hypophosphatasia (HPP) is a rare genetic metabolic bone disorder that is underdiagnosed. Although there are many forms of this disease, based on age of onset, symptoms, and severity, HPP is characterized by low serum alkaline phosphatase levels, bone fractures, and dental complications. Diagnosis of HPP is made from clinical, laboratory, and radiologic findings. Genetic testing for an ALPL gene variant responsible for causing HPP confirms a molecular diagnosis. Distinguishing HPP from other more common bone disorders, such as osteoporosis, is important as the treatment for these diseases differs greatly. Although there is no known cure for HPP, treatment should be holistic and multidisciplinary.
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Affiliation(s)
- Leslie Moro
- University of Tennessee at Chattanooga School of Nursing
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Okawa R, Kadota T, Kurosaka H, Nakayama H, Ochiai M, Ogaya Y, Kubota T, Yamashiro T, Nakano K. Japanese nationwide dental survey of hypophosphatasia reveals novel oral manifestations. Sci Rep 2025; 15:6743. [PMID: 40000791 PMCID: PMC11861587 DOI: 10.1038/s41598-025-91043-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2024] [Accepted: 02/18/2025] [Indexed: 02/27/2025] Open
Abstract
Hypophosphatasia (HPP) is a common inherited skeletal disease. Early exfoliation of primary teeth is known as a dental manifestation of HPP, and sometimes this symptom leads to a diagnosis of HPP. This study aimed to investigate the dental manifestations of HPP in the Japanese population, focusing on dentition and occlusion. A total of 609 dental clinics among general hospitals with dentistry departments were invited to participate. Clinics were sent questionnaires about the number of HPP cases encountered from 2018 to 2022. When clinics indicated that they had treated HPP cases, we proceeded with a second questionnaire about the clinical dental findings of these cases. A total of 103 clinical records of HPP from 30 clinics were collected. Forty percent of non-odonto type cases showed enamel hypomineralization, which was significantly higher than the incidence found in odonto type cases (8.5%) (P < 0.001). Non-odonto type cases also exhibited malocclusion (40.0%), poor oral habits (29.1%), and dysphagia (23.6%). The number of dental visits made by HPP patients is increasing because of the development of new treatments and increased disease awareness. Dental symptoms of HPP vary in severity, with particularly severe forms of HPP associated with enamel hypomineralization, malocclusion, poor oral habits, and dysphagia. Patients with HPP require not only medical collaboration but also multidisciplinary dental care according to the severity of the disease.
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Affiliation(s)
- Rena Okawa
- Department of Pediatric Dentistry, Graduate School of Dentistry, The University of Osaka, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Tamami Kadota
- Department of Pediatric Dentistry, Graduate School of Dentistry, The University of Osaka, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hiroshi Kurosaka
- Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, The University of Osaka, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hirofumi Nakayama
- Department of Pediatrics, Graduate School of Medicine, The University of Osaka, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Marin Ochiai
- Department of Pediatric Dentistry, Graduate School of Dentistry, The University of Osaka, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yuko Ogaya
- Department of Pediatric Dentistry, Graduate School of Dentistry, The University of Osaka, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Takuo Kubota
- Department of Pediatrics, Graduate School of Medicine, The University of Osaka, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Takashi Yamashiro
- Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, The University of Osaka, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Kazuhiko Nakano
- Department of Pediatric Dentistry, Graduate School of Dentistry, The University of Osaka, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
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Cárdenas-Aguilera JG, González-López V, Zarante-Bahamón AM, Prieto-Rivera JC, Baquero-Rodríguez R, Chacón-Acevedo KR, Meza-Martínez AI, Serrano-Gayubo AK, Medina-Orjuela A, Cáceres-Mosquera JA, Guerrero-Tinoco GA, García-Rueda MF, Guarnizo-Zuccardi P, Herrera-Ortiz G, Rojas-Barrera C, Carrascal-Guzmán MI, Reina-Ávila MF, Arguinzoniz-Valenzuela SL, Belmont-Martínez L, Del-Pino M, Viterbo GL, Seijo M, Calzada-Hernández J, Guerra-Hernández NE, Brunetto OH. Diagnosis, treatment, and follow-up of patients with hypophosphatasia. Endocrine 2025; 87:400-419. [PMID: 39663303 PMCID: PMC11811241 DOI: 10.1007/s12020-024-04054-1] [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: 04/04/2024] [Accepted: 09/19/2024] [Indexed: 12/13/2024]
Abstract
INTRODUCTION Hypophosphatasia is a rare inherited systemic metabolic disorder, with an estimated prevalence in the severe forms of the disease of 1/100.000-1/300.000, that affects the typical architecture of bone, leading to defective mineralization during growth and remodeling. It is characterized by loss-of-function variants in the ALPL gene, resulting in low activity of tissue-nonspecific alkaline phosphatase. In severe cases, it can be fatal. OBJECTIVE To generate recommendations on the diagnosis, treatment, and follow-up of patients with hypophosphatasia based on available evidence. MATERIALS AND METHODS A search for evidence published between 2012 and 2024 was carried out in Medline and Embase. The search was expanded with information from various sources, including official sites of development groups, consensuses, technology evaluations, Google Scholar, clinical experts, and reference lists. The quality of the evidence was evaluated according to the type of document type. A modified Delphi consensus process was carried out with external experts, apart from the development group, it was established an 80% agreement threshold to define the final recommendations. RESULTS Sixty-one papers were found in the evidence search. The global quality of the evidence was low. In addition, a consensus was reached on 94 recommendations regarding diagnosis, treatment, and follow-up. Those recommendations were approved by external clinical experts from Colombia, Argentina, Spain, and Mexico. CONCLUSIONS The recommendations proposed in this document are based on the evidence available to the date the search was carried out, and the judgment of clinical experts. The recommendations on diagnosis, treatment, and follow-up are expected to guide the daily clinical practice for patients with HPP.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Mariana Seijo
- Instituto de Inmunología, Genética y Metabolismo, Buenos Aires, Argentina
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Kanabuchi R, Mori Y, Hatakeyama H, Chiba M, Mori N, Aizawa T. Case Report: A Diagnostic Challenge in Adult-Onset Hypophosphatasia With Persistent Polyarthralgia. Int J Rheum Dis 2025; 28:e70136. [PMID: 39953761 DOI: 10.1111/1756-185x.70136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2025] [Revised: 01/29/2025] [Accepted: 02/06/2025] [Indexed: 02/17/2025]
Affiliation(s)
- Ryuichi Kanabuchi
- Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Yu Mori
- Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Hiroshi Hatakeyama
- Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Mishio Chiba
- Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Naoko Mori
- Department of Radiology, Akita University Graduate School of Medicine, Akita, Akita, Japan
| | - Toshimi Aizawa
- Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
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11
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Nakamura-Takahashi A, Ishizuka S, Hirai K, Matsunaga S, Kasahara N, Shintani S, Abe S, Kasahara M. Administration of Bisphosphonate Preparations to Mice with Mild-type Hypophosphatasia Reduces the Quality of Spontaneous Locomotor Activity. Calcif Tissue Int 2025; 116:30. [PMID: 39789326 PMCID: PMC11717816 DOI: 10.1007/s00223-024-01326-w] [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: 06/11/2024] [Accepted: 10/04/2024] [Indexed: 01/12/2025]
Abstract
Hypophosphatasia (HPP) is a congenital bone disease caused by tissue-nonspecific mutations in the alkaline phosphatase gene. It is classified into six types: severe perinatal, benign prenatal, infantile, pediatric, adult, and odonto. HPP with femoral hypoplasia on fetal ultrasonography, seizures, or early loss of primary teeth can be easily diagnosed. In contrast, pediatric, adult, and odonto types of HPP over 4 years of age are less likely to be diagnosed because they do not have typical symptoms. Consequently, it may be misdiagnosed as common osteoporosis, and treatments incompatible with HPP may be implemented. The purpose of this study was to analyze the effects of bisphosphonate preparations administration on the femur of Akp2+/- mice, a mild-type HPP mice model. Zoledronic acid (Zol) was subcutaneously administered to 4-week-old Akp2+/- mice at 1 mg/kg (volume: 200 μL) once a week for a total of 5 times. Afterward, spontaneous locomotor activity analysis was performed, and serum and femur bones were collected at 9 weeks of age. Additionally, micro-computed tomography (CT) analysis, histological analysis, and analysis of the expression levels of various marker proteins and genes were performed. Age-matched Akp2+/+ mice served as controls. The results demonstrated that the administration of Zol to Akp2+/- mice, compared to Akp2+/+ mice, insufficiently promotive bone formation, torn femoral head cartilage, and decreased spontaneous locomotor activity. Therefore, it is important to accurately diagnose patients with mild-type HPP.
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Affiliation(s)
- Aki Nakamura-Takahashi
- Department of Pharmacology, Tokyo Dental College, 2-9-18, Kandamisaki-cho, Chiyoda-ku, Tokyo, 101-0061, Japan.
- Tokyo Dental College Research Branding Project, Tokyo Dental College, Tokyo, Japan.
| | - Satoshi Ishizuka
- Department of Pharmacology, Tokyo Dental College, 2-9-18, Kandamisaki-cho, Chiyoda-ku, Tokyo, 101-0061, Japan
| | - Kengo Hirai
- Department of Pediatric Dentistry, Tokyo Dental College, Tokyo, Japan
| | - Satoru Matsunaga
- Tokyo Dental College Research Branding Project, Tokyo Dental College, Tokyo, Japan
- Department of Anatomy, Tokyo Dental College, Tokyo, Japan
| | - Norio Kasahara
- Tokyo Dental College Research Branding Project, Tokyo Dental College, Tokyo, Japan
- Department of Histology and Developmental Biology, Tokyo Dental College, Tokyo, Japan
| | - Seikou Shintani
- Tokyo Dental College Research Branding Project, Tokyo Dental College, Tokyo, Japan
- Department of Pediatric Dentistry, Tokyo Dental College, Tokyo, Japan
| | - Shinichi Abe
- Tokyo Dental College Research Branding Project, Tokyo Dental College, Tokyo, Japan
- Department of Anatomy, Tokyo Dental College, Tokyo, Japan
| | - Masataka Kasahara
- Department of Pharmacology, Tokyo Dental College, 2-9-18, Kandamisaki-cho, Chiyoda-ku, Tokyo, 101-0061, Japan.
- Tokyo Dental College Research Branding Project, Tokyo Dental College, Tokyo, Japan.
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12
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Imamura H, Adachi T, Zhu W, Yamamoto T, Kanamura N, Onoda H, Nakamura-Takahashi A, Kasahara M, Nakada M, Sato H, Pezzotti G. Raman Spectroscopic Analysis of Molecular Structure and Mechanical Properties of Hypophosphatasia Primary Tooth. Molecules 2024; 29:6049. [PMID: 39770137 PMCID: PMC11678008 DOI: 10.3390/molecules29246049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2024] [Revised: 11/18/2024] [Accepted: 12/11/2024] [Indexed: 01/11/2025] Open
Abstract
Mild hypophosphatasia (HPP) can be difficult to distinguish from other bone disorders in the absence of typical symptoms such as the premature loss of primary teeth. Therefore, this study aimed to analyze the crystallinity of hydroxyapatite (HAp) and the three-dimensional structure of collagen in HPP teeth at the molecular level and to search for new biomarkers of HPP. Raman spectroscopy was used to investigate the molecular structure, composition, and mechanical properties of primary teeth from healthy individuals and patients with HPP. The results showed that the crystallinity of HAp decreased and the carbonate apatite content increased in the region near the dentin-enamel junction (DEJ) of HPP primary teeth. X-ray diffraction (XRD) analyses confirmed a decrease in HAp crystallinity near the DEJ, and micro-computed tomography (CT) scanning revealed a decrease in mineral density in this region. These results suggest incomplete calcification in HPP primary dentin and may contribute to the development of diagnostic and therapeutic agents.
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Affiliation(s)
- Hayata Imamura
- Ceramic Physics Laboratory, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, Kyoto 606-8585, Japan; (H.I.); (W.Z.)
- Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto 602-8566, Japan; (T.Y.); (N.K.); (G.P.)
| | - Tetsuya Adachi
- Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto 602-8566, Japan; (T.Y.); (N.K.); (G.P.)
- Department of Dentistry, Kyoto Prefectural Rehabilitation Hospital for Mentally and Physically Disabled, Naka Ashihara, Joyo 610-0113, Japan
- Department of Immunology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, 465 Kajii-cho, Kyoto 602-8566, Japan
| | - Wenliang Zhu
- Ceramic Physics Laboratory, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, Kyoto 606-8585, Japan; (H.I.); (W.Z.)
| | - Toshiro Yamamoto
- Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto 602-8566, Japan; (T.Y.); (N.K.); (G.P.)
| | - Narisato Kanamura
- Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto 602-8566, Japan; (T.Y.); (N.K.); (G.P.)
| | - Hiroaki Onoda
- Department of Biomolecular Chemistry, Faculty of Science and Technology, Kyoto Prefectural University, 1-5, Shimogamo-nakaragi, Sakyo-ku, Kyoto 606-8522, Japan;
| | - Aki Nakamura-Takahashi
- Department of Pharmacology, Tokyo Dental College, 2-9-18 Kandamisaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan; (A.N.-T.); (M.K.)
| | - Masataka Kasahara
- Department of Pharmacology, Tokyo Dental College, 2-9-18 Kandamisaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan; (A.N.-T.); (M.K.)
| | - Masaru Nakada
- Toray Research Center, Inc., 2-11 Sonoyama 3-chome, Otsu 520-8567, Japan;
| | - Hideo Sato
- Department of Pediatric Dentistry, Kagoshima University Hospital, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan;
| | - Giuseppe Pezzotti
- Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto 602-8566, Japan; (T.Y.); (N.K.); (G.P.)
- Department of Immunology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, 465 Kajii-cho, Kyoto 602-8566, Japan
- Biomedical Engineering Center, Kansai Medical University, 1-9-11 Shin-machi, Hirakata, Osaka 573-1191, Japan
- Department of Orthopedic Surgery, Tokyo Medical University, 6-7-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo 160-0023, Japan
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
- Department of Molecular Science and Nanosystems, Ca’ Foscari University of Venice, Via Torino 155, 30172 Venice, Italy
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13
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Tokuchi S, Kawano T, Ntege EH, Murahashi M, Ide K, Maruyama N, Suzuki R, Takai-Nabeta M, Nabeta T, Tanaka H, Shimizu Y, Nakamura H. Adult-onset hypophosphatasia diagnosed after consecutive tooth loss during orthodontic treatment: a case report. J Med Case Rep 2024; 18:626. [PMID: 39702252 DOI: 10.1186/s13256-024-04948-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Accepted: 10/22/2024] [Indexed: 12/21/2024] Open
Abstract
BACKGROUND Adult hypophosphatasia is an uncommon inherited disorder of mineral homeostasis affecting bone. It arises from mutations within the Alkaline Phosphatase, Biomineralization Associated (ALPL) gene, which encodes tissue-nonspecific alkaline phosphatase. Because of its low prevalence and non-specific clinical manifestations, underdiagnosis and misdiagnosis are frequent, particularly in Asian populations. CASE PRESENTATION We present a case of a 38-year-old Japanese male diagnosed with adult hypophosphatasia following consecutive tooth loss during orthodontic treatment. Genetic analysis revealed a compound heterozygous mutation within the ALPL gene. The patient remained asymptomatic until orthodontic treatment, suggesting that increased mechanical stress overwhelmed residual enzyme activity, triggering the hypophosphatasia symptoms. Asfotase Alfa enzyme replacement therapy improved healing following tooth extraction. CONCLUSION This case highlights the significance of including adult hypophosphatasia in the differential diagnosis for obscure dental complications arising during orthodontic procedures, particularly in Asian patients where certain ALPL variants may be more prevalent. Effective diagnosis and management of adult hypophosphatasia necessitate collaboration between orthodontic practitioners and medical specialists. Improved awareness and a multidisciplinary approach are crucial for timely diagnosis and successful intervention.
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Affiliation(s)
- Shusuke Tokuchi
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nakagami, Nishihara, Okinawa, 903-0215, Japan
| | - Toshihiro Kawano
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nakagami, Nishihara, Okinawa, 903-0215, Japan
| | - Edward Hosea Ntege
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nakagami, Nishihara, Okinawa, 903-0215, Japan
- Plastic and Reconstructive Surgery, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nakagami, Nishihara, Okinawa, 903-0215, Japan
| | - Makoto Murahashi
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nakagami, Nishihara, Okinawa, 903-0215, Japan
| | - Kentaro Ide
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nakagami, Nishihara, Okinawa, 903-0215, Japan
| | - Nobuyuki Maruyama
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nakagami, Nishihara, Okinawa, 903-0215, Japan
| | - Risako Suzuki
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nakagami, Nishihara, Okinawa, 903-0215, Japan
| | - Mirei Takai-Nabeta
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nakagami, Nishihara, Okinawa, 903-0215, Japan
| | - Tsuyoshi Nabeta
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nakagami, Nishihara, Okinawa, 903-0215, Japan
| | - Hideo Tanaka
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nakagami, Nishihara, Okinawa, 903-0215, Japan
| | - Yusuke Shimizu
- Plastic and Reconstructive Surgery, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nakagami, Nishihara, Okinawa, 903-0215, Japan
| | - Hiroyuki Nakamura
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nakagami, Nishihara, Okinawa, 903-0215, Japan.
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14
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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; 194: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] [MESH Headings] [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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15
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Seefried L, Petryk A, Del Angel G, Reder F, Bauer P. Whole genome sequencing in adults with clinical hallmarks of hypophosphatasia negative for ALPL variants. Mol Biol Rep 2024; 51:984. [PMID: 39276275 PMCID: PMC11401779 DOI: 10.1007/s11033-024-09906-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Accepted: 09/03/2024] [Indexed: 09/16/2024]
Abstract
BACKGROUND Hypophosphatasia (HPP) is a rare disease caused by deficient activity of tissue-nonspecific alkaline phosphatase (ALP), encoded by the ALPL gene. The primary objective was to explore novel ALPL variants by whole genome sequencing (WGS) in patients with HPP who previously tested negative by standard methods for ALPL variants. The secondary objective was to search for genes beyond ALPL that may reduce ALP activity or contribute to HPP symptoms. METHODS AND RESULTS WGS was performed in 16 patients clinically diagnosed with HPP who had ALP activity below the normal range and tested negative for ALPL variants. Genetic variants in ALPL and genes possibly associated with low ALP activity or phenotypic overlap with HPP were assessed. All 16 patients had ALP activity below the normal range. WGS did not identify any novel disease-causing ALPL variants. Positive findings for other gene variants were identified in 4 patients: 1 patient presented with variants in COL1A1, NLRP12, and SCN9A, coding for collagen, type, I alpha-1 chain, nod-like receptor pyrin domain containing 12, and sodium voltage-gated channel alpha subunit 9, respectively; 1 presented with a heterozygous, likely pathogenic variant in P3H1 coding for prolyl 3 hydroxylase 1; 1 presented with a heterozygous pathogenic variant in SGCE, coding for sarcoglycan epsilon; and 1 presented with a heterozygous variant of uncertain significance in VDR, encoding vitamin D receptor. CONCLUSION Genomic analysis did not identify novel ALPL variants or a pattern of disease-causing variants in genes other than ALPL to explain the HPP phenotype in these patients. REGISTRATION Clinicaltrials.gov identifier: NCT04925804.
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Affiliation(s)
- Lothar Seefried
- Clinical Trial Unit, Orthopedic Department, University of Würzburg, Brettreichtstr. 11, 97074, Würzburg, Bavaria, Germany.
| | - Anna Petryk
- Alexion, AstraZeneca Rare Disease, Boston, MA, USA
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16
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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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17
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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: 8] [Impact Index Per Article: 8.0] [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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18
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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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19
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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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20
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Baranov AA, Batysheva TT, Bykova OV, Vashakmadze ND, Vislobokova EV, Vitebskaya AV, Vishneva EA, Voynova VY, Zhurkova NV, Zakharova EY, Kisel'nikova LP, Kostik MM, Kutsev SI, Margieva TV, Namazova-Baranova LS, Mikhaylova SV, Moiseev SV, Nagornaya TS, Selimzyanova LR, Semyachkina AN, Smirnova OY, Fedoseenko MV, Pishchal'nikova SV. Modern Approaches to the Management of Children with Hypophosphatasia. PEDIATRIC PHARMACOLOGY 2023; 20:318-336. [DOI: 10.15690/pf.v20i4.2601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2025]
Abstract
Hypophosphatasia is rare genetic disease caused by tissue-nonspecific alkaline phosphatase deficiency due to the mutation in the ALPL gene. Disease can manifest in utero, in childhood or in adults depending on its form and severity. This article presents modern data on the epidemiology, etiology, and clinical signs of hypophosphatasia in children, covers in details differential diagnostic search, and gives guidelines for its evidence-based treatment. Without timely treatment the prognosis of the disease is unfavorable in most cases. Such patients require follow-up by multidisciplinary team of physicians. The only effective method of treatment is enzyme replacement therapy with asfotase alfa. Symptomatic therapy is also crucial as well as physiotherapeutic procedures and therapeutic exercise programs (at rehabilitation stage).
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Affiliation(s)
- Aleksander A. Baranov
- Research Institute of Pediatrics and Children's Health in Petrovsky National Research Centre of Surgery; Sechenov First Moscow State Medical University
| | - Tatiana T. Batysheva
- Scientific and Practical Center for Pediatric Psychoneurology of Moscow Health Department; Russian People's Friendship University
| | - Olga V. Bykova
- Scientific and Practical Center for Pediatric Psychoneurology of Moscow Health Department; Russian People's Friendship University
| | - Nato D. Vashakmadze
- Research Institute of Pediatrics and Children's Health in Petrovsky National Research Centre of Surgery; Pirogov Russian National Research Medical University
| | | | | | - Elena A. Vishneva
- Research Institute of Pediatrics and Children's Health in Petrovsky National Research Centre of Surgery; Pirogov Russian National Research Medical University
| | - Victoria Yu. Voynova
- Pirogov Russian National Research Medical University; Veltischev Research and Clinical Institute for Pediatrics
| | - Natalia V. Zhurkova
- Research Institute of Pediatrics and Children's Health in Petrovsky National Research Centre of Surgery
| | | | | | - Mikhail M. Kostik
- Saint-Petersburg State Pediatric Medical University; Almazov National Medical Research Centre
| | | | - Tea V. Margieva
- Sechenov First Moscow State Medical University; Research and Clinical Institute for Children
| | - Leyla S. Namazova-Baranova
- Research Institute of Pediatrics and Children's Health in Petrovsky National Research Centre of Surgery; Pirogov Russian National Research Medical University
| | - Svetlana V. Mikhaylova
- Moscow State University of Medicine and Dentistry named after A.I. Evdokimov; Russian Children's Clinical Hospital
| | | | | | - Liliia R. Selimzyanova
- Research Institute of Pediatrics and Children's Health in Petrovsky National Research Centre of Surgery; Sechenov First Moscow State Medical University; Pirogov Russian National Research Medical University
| | - Alla N. Semyachkina
- Veltischev Research and Clinical Institute for Pediatrics and Pediatric Surgery
| | - Olga Ya. Smirnova
- Research Institute of Pediatrics and Children's Health in Petrovsky National Research Centre of Surgery
| | - Marina V. Fedoseenko
- Research Institute of Pediatrics and Children's Health in Petrovsky National Research Centre of Surgery; Pirogov Russian National Research Medical University
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21
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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: 2] [Impact Index Per Article: 1.0] [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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22
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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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23
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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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24
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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 2023; 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] [MESH Headings] [Grants] [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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25
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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: 1] [Impact Index Per Article: 0.3] [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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26
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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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27
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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: 1.0] [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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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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29
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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: 0.7] [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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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: 0.3] [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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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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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: 26] [Impact Index Per Article: 6.5] [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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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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34
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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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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: 1.0] [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: 12] [Impact Index Per Article: 3.0] [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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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: 20] [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: 6] [Impact Index Per Article: 1.2] [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: 1.0] [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: 0.2] [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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