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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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Status Epilepticus due to Asfotase Alfa Interruption in Perinatal Severe Hypophosphatasia. Pediatr Neurol 2022; 130:4-6. [PMID: 35303588 DOI: 10.1016/j.pediatrneurol.2021.12.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 12/18/2021] [Accepted: 12/20/2021] [Indexed: 11/20/2022]
Abstract
BACKGROUND Hypophosphatasia (HPP), an inherited, metabolic disorder caused by loss-of-function mutations in the ALPL gene, affects not only bone and tooth mineralization but also central nervous system (CNS) function, resulting in vitamin B6/pyridoxine-responsive seizures. Asfotase alfa treatment mainly improves the skeletal manifestations of HPP. As of yet, there are no reports demonstrating seizure exacerbation caused by asfotase alfa interruption. CASE The patient was a 2-year and 8-month-old female with clinical and genetic diagnosis of perinatal severe HPP. Genetic analysis of ALPL identified compound heterozygous variants. Asfotase alfa and pyridoxine administration begun on postnatal day 2 restored normal development and suppressed seizures except for simple febrile seizures. From age 2 years when her asfotase alfa injections became irregular, she began experiencing seizure exacerbation, including status epilepticus, leading to acute encephalopathy and severe sequelae. The seizure exacerbations always coincided with low alkaline phosphatase (ALP) activity caused by the interruption of asfotase alfa administration. DISCUSSION The clinical course of the present case demonstrated the effect of asfotase alfa on CNS symptoms and a clear correlation between low serum ALP activity and seizure exacerbation. Serum ALP activity measurements were useful as a therapeutic marker in the present case. Furthermore, the risk of seizure exacerbation in the patient could have been predicted, given the genotype-phenotype correlation related to the ALPL gene in the Japanese population. CONCLUSION Regular asfotase alfa injections are needed to prevent seizure exacerbation in patients with HPP. Educating patients and their family about the need for regular asfotase alfa treatment is crucial to preventing disease exacerbation.
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Raimann A, Haberler C, Patsch J, Ertl DA, Sadeghi K, Freilinger M, Lang S, Schmook M, Plecko B, Haeusler G. Lethal Encephalopathy in an Infant with Hypophosphatasia despite Enzyme Replacement Therapy. Horm Res Paediatr 2022; 94:390-398. [PMID: 34673643 DOI: 10.1159/000520341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 10/14/2021] [Indexed: 11/19/2022] Open
Abstract
Hypophosphatasia (HPP) is an inborn error of metabolism caused by loss-of-function mutations in the biomineralization-associated alkaline phosphatase gene, encoding tissue-nonspecific alkaline phosphatase (TNSALP). Symptoms include skeletal hypomineralization and extra-skeletal manifestations such as pyridoxine (B6)-responsive seizures due to impaired cerebral B6 passage. Since the introduction of enzyme replacement therapy (ERT), skeletal manifestations and B6-responsive seizures were reported to improve significantly. Nevertheless, there is an increasing evidence of B6-independent neurological manifestation of HPP including HPP-associated encephalopathy. Here, we present for the first time the brain alterations of an infant with neonatal HPP who died of neurological complications at the age of 5 months despite early initiation of ERT. CSF analysis showed normal concentrations of biogenic amines reflecting sufficient intracellular B6 availability. Postmortem histopathology revealed severe, localized affection of the cerebral cortex including cortical lesions in layers 2 and 3 in direct proximity to TNSALP-expressing neurons and hippocampal sclerosis. Our findings confirm that TNSALP deficiency may lead to a severe encephalopathy. We hypothesize that HPP-associated encephalopathy resistant to currently available ERT may develop in addition and probably independently of typical B6-responsive seizures in some patients. Prospective, controlled studies with close neurological follow-up including brain imaging are needed to identify patients at risk for severe neurological symptoms despite ERT.
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Affiliation(s)
- Adalbert Raimann
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
| | | | - Janina Patsch
- Vienna Bone and Growth Center, Vienna, Austria.,Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Diana-Alexandra Ertl
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
| | - Kambis Sadeghi
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Michael Freilinger
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Susanna Lang
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | - Maria Schmook
- Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Barbara Plecko
- Department of Pediatrics and Adolescent Medicine, Medical University of Graz, Graz, Austria
| | - Gabriele Haeusler
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
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Hasegawa A, Nakamura-Takahashi A, Kasahara M, Saso N, Narisawa S, Millán JL, Samura O, Sago H, Okamoto A, Umezawa A. Prenatal enzyme replacement therapy for Akp2 -/- mice with lethal hypophosphatasia. Regen Ther 2021; 18:168-175. [PMID: 34277899 PMCID: PMC8267436 DOI: 10.1016/j.reth.2021.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/28/2021] [Accepted: 06/06/2021] [Indexed: 11/21/2022] Open
Abstract
Hypophosphatasia (HPP) is a congenital skeletal disease. Impairment of bone mineralization and seizures are due to a deficiency of tissue-nonspecific alkaline phosphatase (TNAP). Enzyme replacement therapy (ERT) is available as a highly successful treatment for pediatric-onset HPP. However, the potential for prenatal ERT has not been fully investigated to date. In this study, we assessed outcomes and maternal safety using a combinational approach with prenatal and postnatal administration of recombinant TNAP in Akp2−/− mice as a model of infantile HPP. For the prenatal ERT, we administered subcutaneous injections of recombinant TNAP to pregnant mice from embryonic day 11.5–14.5 until delivery, and then sequentially to Akp2−/− pups from birth to day 18. For the postnatal ERT, we injected Akp2−/− pups from birth until day 18. Prenatal ERT did not cause any ectopic mineralization in heterozygous maternal mice. Both prenatal and postnatal ERT preserved growth, survival rate and improved bone calcification in Akp2−/− mice. However, the effects of additional prenatal treatment to newborn mice appeared to be minimal, and the difference between prenatal and postnatal ERT was subtle. Further improvement of the prenatal ERT schedule and long-term observation will be required. The present paper sets a standard for such future studies.
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Affiliation(s)
- Akihiro Hasegawa
- Center for Regenerative Medicine, National Center for Child Health and Development Research Institute, Tokyo, Japan.,Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | | | | | - Nana Saso
- Center for Regenerative Medicine, National Center for Child Health and Development Research Institute, Tokyo, Japan
| | - Sonoko Narisawa
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - José Luis Millán
- Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Osamu Samura
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Haruhiko Sago
- Center for Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Tokyo, Japan
| | - Aikou Okamoto
- Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
| | - Akihiro Umezawa
- Center for Regenerative Medicine, National Center for Child Health and Development Research Institute, Tokyo, Japan
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Tanigawa J, Nabatame S, Tominaga K, Nishimura Y, Maegaki Y, Kinosita T, Murakami Y, Ozono K. High-dose pyridoxine treatment for inherited glycosylphosphatidylinositol deficiency. Brain Dev 2021; 43:680-687. [PMID: 33824024 DOI: 10.1016/j.braindev.2021.02.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 02/21/2021] [Accepted: 02/28/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVE We aimed to assess the efficacy and safety of high-dose pyridoxine treatment for seizures and its effects on development in patients with inherited glycosylphosphatidylinositol deficiencies (IGDs). METHODS In this prospective open-label multicenter pilot study, we enrolled patients diagnosed with IGDs using flow cytometry and/or genetic tests. The patients received oral pyridoxine (20-30 mg/kg/day) for 1 year, in addition to previous treatment. RESULTS All nine enrolled patients (mean age: 66.3 ± 44.3 months) exhibited marked decreases in levels of CD16, a glycosylphosphatidylinositol-anchored protein, on blood granulocytes. The underlying genetic causes of IGDs were PIGO, PIGL, and unknown gene mutations in two, two, and five patients, respectively. Six patients experienced seizures, while all patients presented with developmental delay (mean developmental age: 11.1 ± 8.1 months). Seizure frequencies were markedly (>50%) and drastically (>90%) reduced in three and one patients who experienced seizures, respectively. None of the patients presented with seizure exacerbation. Eight of nine patients exhibited modest improvements in development (P = 0.14). No adverse events were observed except for mild transient diarrhea in one patient. CONCLUSION One year of daily high-dose pyridoxine treatment was effective in the treatment of seizures in more than half of our patients with IGDs and modestly improved development in the majority of them. Moreover, such treatment was reasonably safe. These findings indicate that high-dose pyridoxine treatment may be effective against seizures in patients with IGDs, although further studies are required to confirm our findings. (University Hospital Medical Information Network Clinical Trials Registry [UMIN-CTR] number: UMIN000024185.).
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Affiliation(s)
- Junpei Tanigawa
- Department of Pediatrics, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Shin Nabatame
- Department of Pediatrics, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Koji Tominaga
- Department of Pediatrics, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan; Division of Developmental Neuroscience, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yoko Nishimura
- Division of Child Neurology, Institute of Neurological Sciences, Faculty of Medicine, Tottori University, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan
| | - Yoshihiro Maegaki
- Division of Child Neurology, Institute of Neurological Sciences, Faculty of Medicine, Tottori University, 36-1 Nishi-cho, Yonago, Tottori 683-8504, Japan
| | - Taroh Kinosita
- Research Institute for Microbial Diseases and World Premier International Immunology Frontier Research Center, Osaka University, 3-1 Yamadaoka Suita, Osaka 565-0871, Japan
| | - Yoshiko Murakami
- Research Institute for Microbial Diseases and World Premier International Immunology Frontier Research Center, Osaka University, 3-1 Yamadaoka Suita, Osaka 565-0871, Japan
| | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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Chi W, Iyengar ASR, Albersen M, Bosma M, Verhoeven-Duif NM, Wu CF, Zhuang X. Pyridox (am) ine 5'-phosphate oxidase deficiency induces seizures in Drosophila melanogaster. Hum Mol Genet 2020; 28:3126-3136. [PMID: 31261385 DOI: 10.1093/hmg/ddz143] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/31/2019] [Accepted: 06/04/2019] [Indexed: 12/12/2022] Open
Abstract
Pyridox (am) ine 5'-phosphate oxidase (PNPO) is a rate-limiting enzyme in converting dietary vitamin B6 (VB6) to pyridoxal 5'-phosphate (PLP), the biologically active form of VB6 and involved in the synthesis of neurotransmitters including γ-aminobutyric acid (GABA), dopamine, and serotonin. In humans, PNPO mutations have been increasingly identified in neonatal epileptic encephalopathy and more recently also in early-onset epilepsy. Till now, little is known about the neurobiological mechanisms underlying PNPO-deficiency-induced seizures due to the lack of animal models. Previously, we identified a c.95 C>A missense mutation in sugarlethal (sgll)-the Drosophila homolog of human PNPO (hPNPO)-and found mutant (sgll95) flies exhibiting a lethal phenotype on a diet devoid of VB6. Here, we report the establishment of both sgll95 and ubiquitous sgll knockdown (KD) flies as valid animal models of PNPO-deficiency-induced epilepsy. Both sgll95 and sgll KD flies exhibit spontaneous seizures before they die. Electrophysiological recordings reveal that seizures caused by PNPO deficiency have characteristics similar to that in flies treated with the GABA antagonist picrotoxin. Both seizures and lethality are associated with low PLP levels and can be rescued by ubiquitous expression of wild-type sgll or hPNPO, suggesting the functional conservation of the PNPO enzyme between humans and flies. Results from cell type-specific sgll KD further demonstrate that PNPO in the brain is necessary for seizure prevention and survival. Our establishment of the first animal model of PNPO deficiency will lead to better understanding of VB6 biology, the PNPO gene and its mutations discovered in patients, and can be a cost-effective system to test therapeutic strategies.
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Affiliation(s)
- Wanhao Chi
- Committee on Genetics, Genomics and Systems Biology.,Department of Neurobiology, University of Chicago, Chicago, IL, USA
| | - Atulya S R Iyengar
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA, USA
| | - Monique Albersen
- Section Metabolic Diagnostics, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, EA, The Netherlands
| | - Marjolein Bosma
- Section Metabolic Diagnostics, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, EA, The Netherlands
| | - Nanda M Verhoeven-Duif
- Section Metabolic Diagnostics, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, EA, The Netherlands
| | - Chun-Fang Wu
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA, USA
| | - Xiaoxi Zhuang
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
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Michigami T, Tachikawa K, Yamazaki M, Kawai M, Kubota T, Ozono K. Hypophosphatasia in Japan: ALPL Mutation Analysis in 98 Unrelated Patients. Calcif Tissue Int 2020; 106:221-231. [PMID: 31707452 DOI: 10.1007/s00223-019-00626-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 10/24/2019] [Indexed: 12/19/2022]
Abstract
Hypophosphatasia (HPP) is highly variable in clinical expression and is generally classified into six subtypes. Although it would be beneficial to be able to predict the clinical course from the ALPL genotype, studies on this issue are limited. Here, we aimed to clarify the features of Japanese HPP and the relationships between genotype and clinical manifestations. We analyzed 98 unrelated Japanese patients to investigate the percentage of each clinical form, frequently detected mutations, and the relationship between the genotype and phenotype. Some of the identified mutants were characterized by transfection experiments. Perinatal severe form was the most frequent (45.9%), followed by perinatal benign form (22.4%). Among the 196 alleles, p.Leu520ArgfsX86 (c.1559delT) was detected in 89 alleles, and p.Phe327Leu (c.979T>C) was identified in 23 alleles. All of the homozygotes for p.Leu520ArgfsX86 were classified into perinatal severe form, and patients carrying p.Phe327Leu in one of the alleles were classified into perinatal benign or odonto HPP. Twenty of the 22 patients with perinatal benign HPP were compound heterozygous for p.Phe327Leu and another mutation. Most patients with odonto HPP were found to be monoallelic heterozygotes for dominant-negative mutations or compound heterozygotes with mutants having residual activity. The high prevalence of p.Leu520ArgfsX86 and p.Phe327Leu mutations might underlie the high rate of perinatal severe and perinatal benign forms, respectively, in Japanese HPP. Although ALPL genotyping would be beneficial for predicting the clinical course to an extent, the observed phenotypical variability among patients sharing the same genotypes suggests the presence of modifiers.
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Affiliation(s)
- Toshimi Michigami
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka Prefectural Hospital Organization, 840 Murodo-cho, Izumi, 594-1101, Osaka, Japan.
| | - Kanako Tachikawa
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka Prefectural Hospital Organization, 840 Murodo-cho, Izumi, 594-1101, Osaka, Japan
| | - Miwa Yamazaki
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka Prefectural Hospital Organization, 840 Murodo-cho, Izumi, 594-1101, Osaka, Japan
| | - Masanobu Kawai
- Department of Bone and Mineral Research, Research Institute, Osaka Women's and Children's Hospital, Osaka Prefectural Hospital Organization, 840 Murodo-cho, Izumi, 594-1101, Osaka, Japan
| | - Takuo Kubota
- Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, 565-0871, Osaka, Japan
| | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, 565-0871, Osaka, Japan
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Abstract
Introduction: Vitamin B6 dependent epilepsies are a group of treatable diseases (ALDH7A1 deficiency, PNPO deficiency, PLP binding protein deficiency, hyperprolinaemia type II and hypophosphatasia and glycosylphosphatidylinositol anchor synthesis defects) responding to pyridoxine or pyridoxal-5I-phosphate. Areas covered: A critical review was conducted on the therapeutic management of all the reported patients with genetically confirmed diagnoses of diseases affecting vitamin B6 metabolism and presenting with pyridoxine or pyridoxal-5I-phosphate dependent-seizures. Data about safety and efficacy were analyzed as well as the management of supplementation with pyridoxine or pyridoxal-5I-phosphate both in the acute phases and in the maintenance therapies. The authors also analyzed alternative therapeutic strategies for ALDH7A1 deficiency (lysine-restricted diet, arginine supplementation, oligonucleotide antisense therapy, upstream inhibition of aminoadipic semialdehyde synthase). Expert opinion: The administration of pyridoxine or pyridoxal-5I-phosphate should be considered in all intractable seizures also beyond the first year of life. Lysine restricted diet and arginine supplementation should be introduced in all the confirmed ALDH7A1 deficient patients. Pre or post-natal supplementation with pyridoxine should be given in familial cases until an eventual molecular genetic disconfirmation. Minor data about alternative therapies are available for other disorders of vitamin B6 metabolism.
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Affiliation(s)
- Mario Mastrangelo
- Division of Child Neurology and Infantile Psychiatry, Department of Human Neurosciences, Sapienza University of Rome , Roma , Italy
| | - Serena Cesario
- Division of Child Neurology and Infantile Psychiatry, Department of Human Neurosciences, Sapienza University of Rome , Roma , Italy
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Hassel B, Rogne AG, Hope S. Intellectual Disability Associated With Pyridoxine-Responsive Epilepsies: The Need to Protect Cognitive Development. Front Psychiatry 2019; 10:116. [PMID: 30930802 PMCID: PMC6423912 DOI: 10.3389/fpsyt.2019.00116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 02/15/2019] [Indexed: 01/03/2023] Open
Abstract
Pyridoxine (vitamin B6)-responsive epilepsies are severe forms of epilepsy that manifest as seizures immediately after birth, sometimes in utero, sometimes months, or years after birth. Seizures may be treated efficiently by life-long supplementation with pyridoxine or its biologically active form, pyridoxal phosphate, but even so patients may become intellectually disabled, for which there currently is no effective treatment. The condition may be caused by mutations in several genes (TNSALP, PIGV, PIGL, PIGO, PNPO, PROSC, ALDH7A1, MOCS2, or ALDH4A1). Mutations in ALDH7A1, MOCS2, and ALDH4A1 entail build-up of reactive aldehydes (α-aminoadipic semialdehyde, γ-glutamic semialdehyde) that may react non-enzymatically with macromolecules of brain cells. Such reactions may alter the function of macromolecules, and they may produce "advanced glycation end products" (AGEs). AGEs trigger inflammation in the brain. This understanding points to aldehyde-quenching, anti-AGE, or anti-inflammatory therapies as possible strategies to protect cognitive development and prevent intellectual disability in affected children. Studies on how aldehydes traverse cell membranes and how they affect brain function could further the development of therapies for patients with pyridoxine-responsive epilepsies.
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Affiliation(s)
- Bjørnar Hassel
- Department for Neurohabilitation, Oslo University Hospital and University of Oslo, Oslo, Norway.,Norwegian Defence Research Establishment (FFI), Kjeller, Norway
| | - Ane Gretesdatter Rogne
- Department for Neurohabilitation, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Sigrun Hope
- Department for Neurohabilitation, Oslo University Hospital and University of Oslo, Oslo, Norway
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10
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Bowden SA, Foster BL. Alkaline Phosphatase Replacement Therapy for Hypophosphatasia in Development and Practice. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1148:279-322. [PMID: 31482504 DOI: 10.1007/978-981-13-7709-9_13] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Hypophosphatasia (HPP) is an inherited disorder that affects bone and tooth mineralization characterized by low serum alkaline phosphatase. HPP is caused by loss-of-function mutations in the ALPL gene encoding the protein, tissue-nonspecific alkaline phosphatase (TNSALP). TNSALP is expressed by mineralizing cells of the skeleton and dentition and is associated with the mineralization process. Generalized reduction of activity of the TNSALP leads to accumulation of its substrates, including inorganic pyrophosphate (PPi) that inhibits physiological mineralization. This leads to defective skeletal mineralization, with manifestations including rickets, osteomalacia, fractures, and bone pain, all of which can result in multi-systemic complications with significant morbidity, as well as mortality in severe cases. Dental manifestations are nearly universal among affected individuals and feature most prominently premature loss of deciduous teeth. Management of HPP has been limited to supportive care until the introduction of a TNSALP enzyme replacement therapy (ERT), asfotase alfa (AA). AA ERT has proven to be transformative, improving survival in severely affected infants and increasing overall quality of life in children and adults with HPP. This chapter provides an overview of TNSALP expression and functions, summarizes HPP clinical types and pathologies, discusses early attempts at therapies for HPP, summarizes development of HPP mouse models, reviews design and validation of AA ERT, and provides up-to-date accounts of AA ERT efficacy in clinical trials and case reports, including therapeutic response, adverse effects, limitations, and potential future directions in therapy.
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Affiliation(s)
- S A Bowden
- Division of Endocrinology, Department of Pediatrics, Nationwide Children's Hospital/The Ohio State University College of Medicine, Columbus, OH, USA.
| | - B L Foster
- Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
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11
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Akiyama T, Kubota T, Ozono K, Michigami T, Kobayashi D, Takeyari S, Sugiyama Y, Noda M, Harada D, Namba N, Suzuki A, Utoyama M, Kitanaka S, Uematsu M, Mitani Y, Matsunami K, Takishima S, Ogawa E, Kobayashi K. Pyridoxal 5'-phosphate and related metabolites in hypophosphatasia: Effects of enzyme replacement therapy. Mol Genet Metab 2018; 125:174-180. [PMID: 30049651 DOI: 10.1016/j.ymgme.2018.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 07/12/2018] [Accepted: 07/12/2018] [Indexed: 10/28/2022]
Abstract
OBJECTIVE To investigate the utility of serum pyridoxal 5'-phosphate (PLP), pyridoxal (PL), and 4-pyridoxic acid (PA) as a diagnostic marker of hypophosphatasia (HPP) and an indicator of the effect of, and patient compliance with, enzyme replacement therapy (ERT), we measured PLP, PL, and PA concentrations in serum samples from HPP patients with and without ERT. METHODS Blood samples were collected from HPP patients and serum was frozen as soon as possible (mostly within one hour). PLP, PL, and PA concentrations were analyzed using high-performance liquid chromatography with fluorescence detection after pre-column derivatization by semicarbazide. We investigated which metabolites are associated with clinical phenotypes and how these metabolites change with ERT. RESULTS Serum samples from 20 HPP patients were analyzed. The PLP-to-PL ratio and PLP concentration were elevated in all HPP patients. They correlated negatively with serum alkaline phosphatase (ALP) activity and showed higher values in more severe phenotypes (perinatal severe and infantile HPP) compared with other phenotypes. PL concentration was reduced only in perinatal severe HPP. ERT reduced the PLP-to-PL ratio to mildly reduced or low-normal levels and the PLP concentration was reduced to normal or mildly elevated levels. Urine phosphoethanolamine (PEA) concentration did not return to normal levels with ERT in most patients. CONCLUSIONS The serum PLP-to-PL ratio is a better indicator of the effect of ERT for HPP than serum PLP and urine PEA concentrations, and a PLP-to-PL ratio of <4.0 is a good indicator of the effect of, and patient compliance with, ERT.
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Affiliation(s)
- Tomoyuki Akiyama
- Department of Child 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
| | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Toshimi Michigami
- Department of Bone and Mineral Research, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Daisuke Kobayashi
- Department of Food and Chemical Toxicology, School of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Hokkaido, Japan
| | - Shinji Takeyari
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yuichiro Sugiyama
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Masahiro Noda
- Department of Pediatrics, Showa General Hospital, Tokyo, Japan
| | - Daisuke Harada
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Noriyuki Namba
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization (JCHO), Osaka, Japan
| | - Atsushi Suzuki
- Department of Neonatology and Pediatrics, Nagoya City University Graduate School of Medical Sciences, Aichi, Japan
| | - Maiko Utoyama
- Department of Pediatrics, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Sachiko Kitanaka
- Department of Pediatrics, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Mitsugu Uematsu
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Yusuke Mitani
- Department of Pediatrics, Kanazawa University Hospital, Ishikawa, Japan
| | - Kunihiro Matsunami
- Department of Pediatrics, Gifu Prefectural General Medical Center, Gifu, Japan
| | | | - Erika Ogawa
- Department of Pediatrics and Child Health, Nihon University School of Medicine, Tokyo, Japan
| | - Katsuhiro Kobayashi
- Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
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