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Goldberg R, Umarji G, Jabbour S. Heterozygous Hereditary Vitamin D-Dependent Rickets Type 2A (VDDR2A) in a Patient Presenting With Pseudoarthrosis. Case Rep Endocrinol 2025; 2025:2434759. [PMID: 40241811 PMCID: PMC12003035 DOI: 10.1155/crie/2434759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2025] [Accepted: 03/24/2025] [Indexed: 04/18/2025] Open
Abstract
This case report is centered on an atypical presentation of Hereditary Vitamin D-dependent Rickets 2A (VDDR2A), a rare disorder caused by defects in the gene encoding the vitamin D receptor (VDR). While this disorder is primarily autosomal recessive in inheritance, this case demonstrates that a single heterozygous variant in the VDR gene could be linked to both phenotypic and laboratory manifestations of this condition. To understand the pathogenesis of this condition, one must know the typical roles of vitamin D, calcium, and parathyroid hormone (PTH) in maintaining homeostasis in the body. This case report focuses on the underlying pathogenesis of this disorder and demonstrates the variability in the ways this condition can present.
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Affiliation(s)
- Risa Goldberg
- Department of Internal Medicine, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA
| | - Gunjan Umarji
- Division of Endocrinology, Diabetes and Metabolic Disorders, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA
| | - Serge Jabbour
- Division of Endocrinology, Diabetes and Metabolic Disorders, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA
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AlSubaihin A, Harrington J. Hereditary Rickets: A Quick Guide for the Pediatrician. Curr Pediatr Rev 2024; 20:380-394. [PMID: 36475338 DOI: 10.2174/1573396319666221205123402] [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: 04/12/2022] [Revised: 09/10/2022] [Accepted: 11/01/2022] [Indexed: 12/12/2022]
Abstract
With the increased discovery of genes implicated in vitamin D metabolism and the regulation of calcium and phosphate homeostasis, a growing number of genetic forms of rickets are now recognized. These are categorized into calciopenic and phosphopenic rickets. Calciopenic forms of hereditary rickets are caused by genetic mutations that alter the enzymatic activity in the vitamin D activation pathway or impair the vitamin D receptor action. Hereditary forms of phosphopenic rickets, on the other hand, are caused by genetic mutations that lead to increased expression of FGF23 hormone or that impair the absorptive capacity of phosphate at the proximal renal tubule. Due to the clinical overlap between acquired and genetic forms of rickets, identifying children with hereditary rickets can be challenging. A clear understanding of the molecular basis of hereditary forms of rickets and their associated biochemical patterns allow the health care provider to assign the correct diagnosis, avoid non-effective interventions and shorten the duration of the diagnostic journey in these children. In this mini-review, known forms of hereditary rickets listed on the Online Mendelian Inheritance in Man database are discussed. Further, a clinical approach to identify and diagnose children with hereditary forms of rickets is suggested.
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Affiliation(s)
- Abdulmajeed AlSubaihin
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
- King Saud University Medical City, Riyadh, Saudi Arabia
| | - Jennifer Harrington
- Division of Endocrinology, Women's and Children's Health Network, North Adelaide, Australia
- Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, Australia
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Hanna AE, Sanjad S, Andary R, Nemer G, Ghafari JG. Tooth Development Associated with Mutations in Hereditary Vitamin D-Resistant Rickets. JDR Clin Trans Res 2018; 3:28-34. [PMID: 30938651 DOI: 10.1177/2380084417732510] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Hereditary vitamin D-resistant rickets (HVDRR) is a rare genetic disorder caused by mutations at the level of the vitamin D receptor ( VDR) gene. The disease is characterized by refractory hypocalcemia, elevated serum levels of 1,25-dihydroxy-vitamin D, retarded growth, sparse body hair (sometimes alopecia), premature tooth loss, enlarged pulp chambers, thin dentine, and hypoplastic enamel. The aims of this study were 1) to document the dental development of children with HVDRR in association with the mutation type within the VDR and 2) to evaluate the association between dental development and the timing of and response to HVDRR treatment. Genome analysis was performed for 4 affected children (2 y 2 mo to 6 y 8 mo) under treatment with high doses of vitamin D and calcium. Longitudinal records of clinical and radiographic data on their dental development were assessed in relation to genetic profile and response to treatment. Treatment success depended on the position of the mutation within the VDR protein: children with the p.R391S mutation had a favorable outcome but maintained alopecia totalis, while 1 child with the p.H397P mutation and normal hair had no response to very high doses of vitamin D. The primary incisors, formed prenatally and first to emerge, were missing in 3 children and mobile in 1 child; parents reported loss within months posteruption. Posterior teeth were present, having erupted after treatment initiation. Hypoplastic enamel in emerging teeth was associated with late treatment onset. Mutation type in the VDR gene appears to be related to differences in the disease phenotype and response to treatment. Dental development represents an indicator of the disease process, initially protected by maternal blood levels of calcium and later restored by therapeutic supplies that normalize these levels. Knowledge Transfer Statement: Two novel mutations were associated with different HVDRR phenotypes, one of which responded positively to treatment. Early detection of the mutation should help pediatricians forecast treatment protocol and response. The results also highlight the direct relationship between dental development and blood calcium levels, underscoring the importance of early diagnosis and treatment of HVDRR to minimize the loss of primary teeth and reduce structural abnormalities of permanent teeth.
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Affiliation(s)
- A E Hanna
- 1 Division of Orthodontics and Dentofacial Orthopedics, Department of Otolaryngology and Head and Neck Surgery, American University of Beirut Medical Center, Beirut, Lebanon
| | - S Sanjad
- 2 Department of Pediatrics and Adolescent Medicine, American University of Beirut Medical Center, Beirut, Lebanon
| | - R Andary
- 3 Private practice, Aley Mount, Lebanon
| | - G Nemer
- 4 Department of Biochemistry and Molecular Genetics, American University of Beirut Medical Center, Beirut, Lebanon
| | - J G Ghafari
- 1 Division of Orthodontics and Dentofacial Orthopedics, Department of Otolaryngology and Head and Neck Surgery, American University of Beirut Medical Center, Beirut, Lebanon
- 5 School of Dentistry, Lebanese University, Beirut, Lebanon
- 6 Department of Orthodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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4
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Functional Analysis of VDR Gene Mutation R343H in A Child with Vitamin D-Resistant Rickets with Alopecia. Sci Rep 2017; 7:15337. [PMID: 29127362 PMCID: PMC5681508 DOI: 10.1038/s41598-017-15692-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 11/01/2017] [Indexed: 11/09/2022] Open
Abstract
The functional study of different mutations on vitamin D receptor (VDR) gene causing hereditary vitamin D-resistant rickets (HVDRR) remains limited. This study was to determine the VDR mutation and the mechanisms of this mutation-causing phenotype in a family with HVDRR and alopecia. Phenotype was analyzed, and in vitro functional studies were performed. The proband and his affected sister exhibited typical HVDRR with alopecia, and their biochemical and radiographic abnormalities but not alopecia responded to supraphysiological doses of active vitamin D3. A novel homozygous missense R343H mutation in the exon 9 of VDR residing in the retinoid X receptor (RXR)-binding domain was identified. The expression level and C-terminal conformation of R343H mutant are not different from the wild-type VDR. This mutant had no effect on the nuclear localization of VDR, VDR-RXR heterodimerization, but it impaired CYP24A1 promoter activity in the presence of 1,25 (OH)2 vitamin D3, at least in part, mediated through specific nuclear receptor coactivator. Simulation models revealed the vanished interaction between guanidinium group of R343 and carboxyl group of E269. Without affecting the expression, conformation, nuclear location of VDR or heteridimerization with RXR, VDR-R343H impairs the transactivation activity of VDR on downstream transcription, accounting for HVDRR features with alopecia.
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Rochel N, Molnár F. Structural aspects of Vitamin D endocrinology. Mol Cell Endocrinol 2017; 453:22-35. [PMID: 28257826 DOI: 10.1016/j.mce.2017.02.046] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/27/2017] [Accepted: 02/27/2017] [Indexed: 12/12/2022]
Abstract
1α,25-Dihydroxvitamin D3 (1,25(OH)2D3) is the hormonally active form of vitamin D3. Its synthesis and its metabolites, their transport and elimination as well as action on transcriptional regulation involves the harmonic cooperation of diverse proteins with vitamin D binding capacities such as vitamin D binding protein (DBP), cytochrome P450 enzymes or the nuclear vitamin receptor (VDR). The genomic mechanism of 1,25(OH)2D3 action involves its binding to VDR that functionally acts as a heterodimer with retinoid X receptor. The crystal structures of the most important proteins for vitamin D3, VDR, DBP, CYP2R1 and CYP24A1, have provided identification of mechanisms of actions of these proteins and those mediating VDR-regulated transcription. This review will present the structural information on recognition of the vitamin D3 and metabolites by CYP proteins and DBP as well as the structural basis of VDR activation by 1,25(OH)2D3 and metabolites. Additionally, we will describe, the implications of the VDR mutants associated with hereditary vitamin D-resistant rickets (HVDRR) that display impaired function.
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Affiliation(s)
- Natacha Rochel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Institut National de La Santé et de La Recherche Médicale (INSERM), U964/Centre National de Recherche Scientifique (CNRS), UMR7104/Université de Strasbourg, 67404 Illkirch, France.
| | - Ferdinand Molnár
- Institute of Biopharmacy, School of Pharmacy, Faculty of Heath Science, University of Eastern Finland, Yliopistonranta 1C, Canthia 2036, 70210 Kuopio, Finland.
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Kinoshita Y, Ito N, Makita N, Nangaku M, Fukumoto S. Changes in bone metabolic parameters following oral calcium supplementation in an adult patient with vitamin D-dependent rickets type 2A. Endocr J 2017; 64:589-596. [PMID: 28367941 DOI: 10.1507/endocrj.ej16-0583] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Vitamin D-dependent rickets type 2A (VDDR2A) is a rare inherited disorder with decreased tissue responsiveness to 1,25-dihydroxyvitamin D [1,25(OH)2D], caused by loss of function mutations in the vitamin D receptor (VDR) gene. Approximately 50 types of mutations have been identified so far that change amino acids in either the N-terminal DNA binding domain (DBD) or the C-terminal ligand binding domain (LBD) of the VDR protein. The degree of responsiveness to 1,25(OH)2D varies between patients with VDDR2A, which may depend on their residual VDR function. In this report, we describe a female patient with VDDR2A caused by an early stop codon (R30X) in the VDR gene that resulted in a severely truncated VDR protein. She developed alopecia and bowed legs within a year after birth and was diagnosed with rickets at the age of 2. She had been treated with active vitamin D and oral calcium supplementation until 22 years of age, when she developed secondary hyperparathyroidism and high bone turnover. The genetic diagnosis of VDDR2A promoted the discontinuation of active vitamin D treatment in favor of monotherapy with oral calcium supplementation. We observed amelioration of the secondary hyperparathyroidism and normalization of bone metabolic parameters within 6 years.
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Affiliation(s)
- Yuka Kinoshita
- Division of Nephrology & Endocrinology, Department of Medicine, the University of Tokyo Hospital, Tokyo, Japan
| | - Nobuaki Ito
- Division of Nephrology & Endocrinology, Department of Medicine, the University of Tokyo Hospital, Tokyo, Japan
| | - Noriko Makita
- Division of Nephrology & Endocrinology, Department of Medicine, the University of Tokyo Hospital, Tokyo, Japan
| | - Masaomi Nangaku
- Division of Nephrology & Endocrinology, Department of Medicine, the University of Tokyo Hospital, Tokyo, Japan
| | - Seiji Fukumoto
- Fujii Memorial Institute of Medical Sciences, Tokushima University, Tokushima, Japan
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Akıncı A, Dündar İ, Kıvılcım M. The Effectiveness of Cinacalcet as an Adjunctive Therapy for Hereditary 1,25 Dihydroxyvitamin D3-Resistant Rickets. J Clin Res Pediatr Endocrinol 2017; 9:172-178. [PMID: 27796266 PMCID: PMC5463292 DOI: 10.4274/jcrpe.3486] [Citation(s) in RCA: 8] [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] [Indexed: 12/01/2022] Open
Abstract
High doses of oral calcium or long-term calcium infusions are recommended to correct the hypocalcemia and secondary hyperparathyroidism in patients with hereditary 1,25 dihydroxyvitamin D3-resistant rickets (HVDRR). Preliminary studies revealed that calcimimetics may be a safe and effective therapeutic choice in children with secondary hyperparathyroidism. Our aim was to observe the efficacy of cinacalcet in the normalization of secondary hyperparathyroidism and hypophosphatemia in two siblings aged 2.5 years and 6 months with HVDRR who did not respond to traditional treatment regimes. Both patients were admitted to the hospital with severe hypocalcemia. They were treated with high doses of calcitriol and calcium infusions intravenously. Secondary hyperparathyroidism was normalized temporarily, but did not improve completely. Cinacalcet (0.25 mg/kg) once a day along with the high doses of oral calcium and calcitriol was added to the treatment schedule. After 3 months, biochemical and radiologic findings reverted to normal. Our findings indicate that cinacalcet is effective in normalizing the hyperparathyroidism and hypophosphatemia in these cases and in improving the bone pathology.
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Affiliation(s)
- Ayşehan Akıncı
- İnönü University Faculty of Medicine, Department of Pediatric Endocrinology, Malatya, Turkey, E-mail:
| | - İsmail Dündar
- Inönü University Faculty of Medicine, Department of Pediatric Endocrinology, Malatya, Turkey
| | - Meltem Kıvılcım
- İnönü University Faculty of Medicine, Department of Developmental and Behavioral, Malatya, Turkey
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Belorusova AY, Rochel N. Structural Studies of Vitamin D Nuclear Receptor Ligand-Binding Properties. VITAMINS AND HORMONES 2015; 100:83-116. [PMID: 26827949 DOI: 10.1016/bs.vh.2015.10.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The vitamin D nuclear receptor (VDR) and its natural ligand, 1α,25-dihydroxyvitamin D3 hormone (1,25(OH)2D3, or calcitriol), classically regulate mineral homeostasis and metabolism but also much broader range of biological functions, such as cell growth, differentiation, antiproliferation, apoptosis, adaptive/innate immune responses. Being widely expressed in various tissues, VDR represents an important therapeutic target in the treatment of diverse disorders. Since ligand binding is a key step in VDR-mediated signaling, numerous 1,25(OH)2D3 analogs have been synthesized in order to selectively modulate the receptor activity. Most of the synthetic analogs have been developed by modification of a parental compound and some of them mimic 1,25(OH)2D3 scaffold without being structurally related to it. The ability of ligands that have different size and conformation to bind to VDR and to demonstrate biological effects is intriguing, and therefore, ligand-binding properties of the receptor have been extensively investigated using a variety of biochemical, biophysical, and computational methods. In this chapter, we describe different aspects of the structure-function relationship of VDR in complex with natural and synthetic ligands coming from structural analysis. With the emphasis on the binding modes of the most promising compounds, such as secosteroidal agonists and 1,25(OH)2D3 mimics, we also highlight the action of VDR antagonists and the evidence for the existence of an alternative ligand-binding site within the receptor. Additionally, we describe the crystal structures of VDR mutants associated with hereditary vitamin D-resistant rickets that display impaired ligand-binding function.
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Affiliation(s)
- Anna Y Belorusova
- Department of Integrative Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Institut National de Santé et de Recherche Médicale (INSERM) U964, Centre National de Recherche Scientifique (CNRS) UMR 7104, Université de Strasbourg, Illkirch, France
| | - Natacha Rochel
- Department of Integrative Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Institut National de Santé et de Recherche Médicale (INSERM) U964, Centre National de Recherche Scientifique (CNRS) UMR 7104, Université de Strasbourg, Illkirch, France.
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9
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Papadopoulou A, Bountouvi E, Gole E, Doulgeraki A, Tournis S, Papadimitriou A, Nicolaidou P. Identification of a novel nonsense mutation in the ligand-binding domain of the vitamin d receptor gene and clinical description of two greek patients with hereditary vitamin d-resistant rickets and alopecia. Horm Res Paediatr 2015; 82:206-12. [PMID: 25060608 DOI: 10.1159/000362618] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 04/01/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS We analyzed the vitamin D receptor (VDR) gene in 2 Greek patients who exhibited the classical features of hereditary vitamin D-resistant rickets (HVDRR) type II, including severe bone deformities and alopecia. We also describe the clinical phenotypes and the response to treatment of our patients. METHODS Genomic DNA was extracted from peripheral blood samples of both patients. Coding region and flanking introns of VDR gDNA was amplified and direct sequenced. RESULTS A unique cytosine to thymine (C>T) transition was identified at nucleotide position 1066 (c.1066C>T) in the ligand-binding domain of the VDR gene of both patients, predicting the substitution of a glutamine to a terminal codon at position 356 (Gln356stop). CONCLUSIONS The novel nonsense mutation c.1066C>T (Gln356stop) is expected to result in a VDR protein 71 amino acids shorter and thus to affect the normal VDR function. In particular, the missing protein part alters the VDR heterodimerization with the retinoid X receptor which has been correlated with the presence of alopecia. Both patients were introduced to treatment with supraphysiological doses of 1α-calcidiol which improved their clinical phenotypes except for alopecia.
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Affiliation(s)
- Anna Papadopoulou
- Third Department of Pediatrics, Athens University Medical School, 'Attikon' University General Hospital, Athens, Greece
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Mazen I, Ismail S, Amr K, El Gammal M, Abdel-Hamid M. Hereditary 1,25-dihydroxyvitamin D-resistant rickets with alopecia in four Egyptian families: report of three novel mutations in the vitamin D receptor gene. J Pediatr Endocrinol Metab 2014; 27:873-8. [PMID: 24859502 DOI: 10.1515/jpem-2013-0443] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 04/01/2014] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To study the vitamin D receptor (VDR) gene in five Egyptian patients with severe rickets and the clinical features of hereditary vitamin D-resistant rickets, including hypocalcemia, hypophosphatemia, total alopecia, and elevated serum levels of 1,25-dihydroxyvitamin D. STUDY DESIGN We amplified and sequenced DNA samples from blood from the patients, their parents, and available family members. RESULTS DNA sequence analyses of the VDR gene showed three novel mutations (p.Y295X, p.R343C, and p.R391H) and a previously reported one (p.R30X) in four patients, whereas no mutation was found in one patient. Mutations cosegregated perfectly with affected individuals in all families, and did not exist in unaffected family members or 200 ethnically matched chromosomes. CONCLUSION Three novel deleterious mutations in the VDR ligand-binding domain were identified, which are expected to render the VDR nonfunctional. Successful treatment with frequent high doses of oral calcium and calcidol was evident in all patients; however, hair growth occurred only in one patient.
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11
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Mutations in the vitamin D receptor and hereditary vitamin D-resistant rickets. BONEKEY REPORTS 2014; 3:510. [PMID: 24818002 DOI: 10.1038/bonekey.2014.5] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 09/27/2013] [Indexed: 12/24/2022]
Abstract
Heterogeneous loss of function mutations in the vitamin D receptor (VDR) interfere with vitamin D signaling and cause hereditary vitamin D-resistant rickets (HVDRR). HVDRR is characterized by hypocalcemia, secondary hyperparathyroidism and severe early-onset rickets in infancy and is often associated with consanguinity. Affected children may also exhibit alopecia of the scalp and total body. The children usually fail to respond to treatment with calcitriol; in fact, their endogenous levels are often very elevated. Successful treatment requires reversal of hypocalcemia and secondary hyperparathyroidism and is usually accomplished by administration of high doses of calcium given either intravenously or sometimes orally to bypass the intestinal defect in VDR signaling.
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Malloy PJ, Tasic V, Taha D, Tütüncüler F, Ying GS, Yin LK, Wang J, Feldman D. Vitamin D receptor mutations in patients with hereditary 1,25-dihydroxyvitamin D-resistant rickets. Mol Genet Metab 2014; 111:33-40. [PMID: 24246681 PMCID: PMC3933290 DOI: 10.1016/j.ymgme.2013.10.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 10/22/2013] [Accepted: 10/23/2013] [Indexed: 02/06/2023]
Abstract
CONTEXT Hereditary vitamin D resistant rickets (HVDRR), also known as vitamin D-dependent rickets type II, is an autosomal recessive disorder characterized by the early onset of rickets with hypocalcemia, secondary hyperparathyroidism and hypophosphatemia and is caused by mutations in the vitamin D receptor (VDR) gene. The human gene encoding the VDR is located on chromosome 12 and comprises eight coding exons and seven introns. OBJECTIVES, PATIENTS, AND METHODS We analyzed the VDR gene of 5 previously unreported patients, two from Singapore and one each from Macedonia (former Yugoslav Republic), Saudi Arabia and Turkey. Each patient had clinical and radiographic features of rickets, hypocalcemia, and the 4 cases that had the measurement showed elevated serum concentrations of 1,25-dihydroxyvitamin D (1,25(OH)(2)D). Mutations were re-created in the WT VDR cDNA and examined for 1,25(OH)(2)D(3)-mediated transactivation in COS-7 monkey kidney cells. RESULTS Direct sequencing identified four novel mutations and two previously described mutations in the VDR gene. The novel mutations included a missense mutation in exon 3 causing the amino acid change C60W; a missense mutation in exon 4 causing the amino acid change D144N; a missense mutation in exon 7 causing the amino acid change N276Y; and a 2bp deletion in exon 3 5'-splice site (IVS3∆+4-5) leading to a premature stop. CONCLUSIONS These 4 unique mutations add to the previous 45 mutations identified in the VDR gene in patients with HVDRR.
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Affiliation(s)
- Peter J Malloy
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Velibor Tasic
- Department of Pediatric Nephrology, Clinic for Children's Diseases, University Children's Hospital, Medical School of Skopje, Skopje, Macedonia
| | - Doris Taha
- Department of Endocrinology, Children's Hospital of Michigan, Detroit, MI 48201, USA
| | - Filiz Tütüncüler
- Pediatric Endocrinology, Trakya University, Faculty of Medicine, Edirne, Turkey
| | - Goh Siok Ying
- Department of Pediatrics, University Children's Medical Institute, National University Hospital, Singapore
| | - Loke Kah Yin
- Department of Pediatrics, University Children's Medical Institute, National University Hospital, Singapore
| | - Jining Wang
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - David Feldman
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
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13
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Aoi N, Inoue K, Chikanishi T, Fujiki R, Yamamoto H, Kato H, Eto H, Doi K, Itami S, Kato S, Yoshimura K. 1α,25-dihydroxyvitamin D3 modulates the hair-inductive capacity of dermal papilla cells: therapeutic potential for hair regeneration. Stem Cells Transl Med 2012. [PMID: 23197867 DOI: 10.5966/sctm.2012-0032] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Dermal papilla cells (DPCs) have the potential to induce differentiation of epithelial stem cells into hair, and Wnt signaling is deeply involved in the initiation process. The functional limitation of expanded adult DPCs has been a difficult challenge for cell-based hair regrowth therapy. We previously reported that 1α,25-dihydroxyvitamin D(3) (VD(3)) upregulates expression of transforming growth factor (TGF)-β2 and alkaline phosphatase (ALP) activity, both features of hair-inducing human DPCs (hDPCs). In this study, we further examined the effects and signaling pathways associated with VD(3) actions on DPCs. VD(3) suppressed hDPC proliferation in a dose-dependent, noncytotoxic manner. Among the Wnt-related genes investigated, Wnt10b expression was significantly upregulated by VD(3) in hDPCs. Wnt10b upregulation, as well as upregulation of ALPL (ALP, liver/bone/kidney) and TGF-β2, by VD(3) was specific in hDPCs and not detected in human dermal fibroblasts. Screening of paracrine or endocrine factors in the skin indicated that all-trans retinoic acid (atRA) upregulated Wnt10b gene expression, although synergistic upregulation (combined atRA and VD(3)) was not seen. RNA interference with vitamin D receptor (VDR) revealed that VD(3) upregulation of Wnt10b, ALPL, and TGF-β2 was mediated through the genomic VDR pathway. In a rat model of de novo hair regeneration by murine DPC transplantation, pretreatment with VD(3) significantly enhanced hair folliculogenesis. Specifically, a greater number of outgrowing hair shafts and higher maturation of regenerated follicles were observed. Together, these data suggest that VD(3) may promote functional differentiation of DPCs and be useful in preserving the hair follicle-inductive capacity of cultured DPCs for hair regeneration therapies.
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Affiliation(s)
- Noriyuki Aoi
- Department of Plastic Surgery, University of Tokyo, Tokyo, Japan
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Abstract
The biochemical and genetic analysis of the VDR in patients with HVDRR has yielded important insights into the structure and function of the receptor in mediating 1,25(OH)2D3 action. Similarly, study of children affected by HVDRR continues to provide a more complete understanding of the biologic role of 1,25(OH)2D3 in vivo. A concerted investigative approach to HVDRR at the clinical, cellular, and molecular levels has proved valuable in gaining knowledge of the functions of the domains of the VDR and elucidating the detailed mechanism of action of 1,25(OH)2D3. These studies have been essential to promote the well-being of the families with HVDRR and in improving the diagnostic and clinical management of this rare genetic disease.
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15
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Supornsilchai V, Hiranras Y, Wacharasindhu S, Mahayosnond A, Suphapeetiporn K, Shotelersuk V. Two siblings with a novel nonsense mutation, p.R50X, in the vitamin D receptor gene. Endocrine 2011; 40:62-6. [PMID: 21424181 DOI: 10.1007/s12020-011-9450-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2011] [Accepted: 03/02/2011] [Indexed: 10/18/2022]
Abstract
Hereditary vitamin D-resistant rickets (HVDRR), an autosomal recessive disorder caused by inactivating mutations in the vitamin D receptor (VDR) gene. We identified two affected children from the same family, one at the age of 10 years and 9 months and the other at 9 months old. Mutation analysis by PCR-sequencing the entire coding region of the VDR gene revealed a homozygous C to T transition in exon 2 of the VDR gene (c.148C>T) resulting in a stop codon at amino acid position 50 (p.R50X) in the proband and his younger sister. The p.R50X has never been previously described. Both asymptomatic parents were heterozygous for the mutation. In addition to most of the clinical features of HVDRR including total alopecia, symptoms of hypocalcemia at a later onset and normophosphatemia, rarely found in HVDRR were present in the proband. This study also emphasizes an important role of genetic testing for early diagnosis and genetic counseling.
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Affiliation(s)
- Vichit Supornsilchai
- Division of Endocrinology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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Song JK, Yoon KS, Shim KS, Bae CW. Novel compound heterozygous mutations in the vitamin D receptor gene in a Korean girl with hereditary vitamin D resistant rickets. J Korean Med Sci 2011; 26:1111-4. [PMID: 21860566 PMCID: PMC3154351 DOI: 10.3346/jkms.2011.26.8.1111] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 06/21/2011] [Indexed: 11/20/2022] Open
Abstract
Hereditary vitamin D resistant rickets (HVDRR) is a rare genetic disorder caused by a mutation of vitamin D receptor (VDR) gene. A number of cases had been reported in many countries but not in Korea. We examined a three-year old Korean girl who had the typical clinical features of HVDRR including rickets, hypocalcemia, hypophosphatemia, elevated serum calcitriol level and secondary hyperparathyroidism. The girl and her father were both heterozygous for the 719C-to-T(I146T)---> c.437C > T(p.T1461) [corrected] mutation in exon 4, whereas she and her mother were both heterozygous for 754C-to-T (R154C)---> c.472 > T(p.R158C) [corrected] mutation in exon 5 of the VDR gene. In this familial study, we concluded that the girl had compound heterozygous mutations in her VDR gene which caused HVDRR. This is the first report of a unique mutation in the VDR gene in Korea.
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Affiliation(s)
- Jun Kyu Song
- Department of Biochemistry and Molecular Biology, Kyung Hee University School of Medicine, Seoul, Korea
| | - Kyung Sik Yoon
- Department of Biochemistry and Molecular Biology, Kyung Hee University School of Medicine, Seoul, Korea
| | - Kye Shik Shim
- Department of Pediatrics, Kyung Hee University School of Medicine, Seoul, Korea
| | - Chong-Woo Bae
- Department of Pediatrics, Kyung Hee University School of Medicine, Seoul, Korea
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Aljubeh JM, Wang J, Al-Remeithi SS, Malloy PJ, Feldman D. Report of two unrelated patients with hereditary vitamin D resistant rickets due to the same novel mutation in the vitamin D receptor. J Pediatr Endocrinol Metab 2011; 24:793-9. [PMID: 22145479 DOI: 10.1515/jpem.2011.341] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND/AIMS Two unrelated patients found to have hereditary vitamin D resistant rickets (HVDRR) were admitted to our hospital. METHODS This article describes the diagnosis, management and molecular basis for their disease. RESULTS Both patients had severe growth and motor developmental retardation, rickets with chest deformities and pulmonary abnormalities, but no alopecia. Both had hypocalcemia, secondary hyperparathyroidism and susceptibility to pulmonary infections. In both cases, good response with normalization of abnormal biochemistries and healing of rickets was achieved with IV calcium infusion. Subsequently, improvement was maintained with oral calcium. Both children harbored the same unique missense mutation in the vitamin D receptor (VDR) gene that substituted arginine with histidine at amino acid 274 (R274H) in the VDR ligand-binding domain (LBD). R274 is a contact point for the 1alpha-hydroxyl group of 1,25(OH)2D3, the active ligand for the VDR. Functional analyses of the R274H mutation revealed a 100-fold decrease in activity compared to wild-type VDR. CONCLUSION We describe a novel missense mutation at R274H in the VDR gene that resulted in the HVDRR syndrome in two unrelated children. Vigorous treatment using IV calcium to normalize their hypocalcemia achieved dramatic improvement in these complex and severely ill patients.
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Affiliation(s)
- Jamal M Aljubeh
- Division of Endocrinology, Pediatrics Institute, Sheikh Khalifah Medical City, Abu Dhabi, United Arab Emirates.
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Forghani N, Lum C, Krishnan S, Wang J, Wilson DM, Blackett PR, Malloy PJ, Feldman D. Two new unrelated cases of hereditary 1,25-dihydroxyvitamin D-resistant rickets with alopecia resulting from the same novel nonsense mutation in the vitamin D receptor gene. J Pediatr Endocrinol Metab 2010; 23:843-50. [PMID: 21073129 DOI: 10.1515/jpem.2010.136] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) an important regulator of bone homeostasis, mediates its actions by binding to the vitamin D receptor (VDR), a nuclear transcription factor. Mutations in the VDR cause the rare genetic disease hereditary vitamin D resistant rickets (HVDRR). In this study, we examined two unrelated young female patients who exhibited severe early onset rickets, hypocalcemia, and hypophosphatemia. Both patients had partial alopecia but with different unusual patterns of scant hair. Sequencing of the VDR gene showed that both patients harbored the same unique nonsense mutation that resulted in a premature stop codon (R50X). Skin fibroblasts from patient #1 were devoid of VDR protein and 1,25(OH)2D3 treatment of these cells failed to induce CYP24A1 gene expression, a marker of 1,25(OH)2D3 action. In conclusion, we identified a novel nonsense mutation in the VDR gene in two patients with HVDRR and alopecia. The mutation truncates the VDR protein and causes 1,25(OH)2D3 resistance.
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Affiliation(s)
- Nikta Forghani
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94305, USA
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Abstract
Two rare genetic diseases can cause rickets in children. The critical enzyme to synthesize calcitriol from 25-hydroxyvitamin D, the circulating hormone precursor, is 25-hydroxyvitamin D-1alpha-hydroxylase (1alpha-hydroxylase). When this enzyme is defective and calcitriol can no longer be synthesized, the disease 1alpha-hydroxylase deficiency develops. The disease is also known as vitamin D-dependent rickets type 1 or pseudovitamin D deficiency rickets. When the VDR is defective, the disease hereditary vitamin D-resistant rickets, also known as vitamin D-dependent rickets type 2, develops. Both diseases are rare autosomal recessive disorders characterized by hypocalcemia, secondary hyperparathyroidism, and early onset severe rickets. In this article, these 2 genetic childhood diseases, which present similarly with hypocalcemia and rickets in infancy, are discussed and compared.
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Affiliation(s)
- Peter J Malloy
- Division of Endocrinology, Gerontology and Metabolism, Stanford University School of Medicine, Stanford University, S-025 Endocrinology, Stanford, CA 94305-5103, USA.
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LeVine DN, Zhou Y, Ghiloni RJ, Fields EL, Birkenheuer AJ, Gookin JL, Roberston ID, Malloy PJ, Feldman D. Hereditary 1,25-dihydroxyvitamin D-resistant rickets in a Pomeranian dog caused by a novel mutation in the vitamin D receptor gene. J Vet Intern Med 2010; 23:1278-83. [PMID: 19909429 DOI: 10.1111/j.1939-1676.2009.0405.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- D N LeVine
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA.
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Kanakamani J, Tomar N, Kaushal E, Tandon N, Goswami R. Presence of a deletion mutation (c.716delA) in the ligand binding domain of the vitamin D receptor in an Indian patient with vitamin D-dependent rickets type II. Calcif Tissue Int 2010; 86:33-41. [PMID: 19921089 DOI: 10.1007/s00223-009-9310-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Accepted: 10/15/2009] [Indexed: 10/20/2022]
Abstract
Vitamin D-dependent rickets type II (VDDR-type II) is a rare disorder caused by mutations in the vitamin D receptor (VDR) gene. Here, we describe a patient with VDDR-type II with severe alopecia and rickets. She had hypocalcemia, hypophosphatemia, secondary hyperparathyroidism, and elevated serum alkaline phosphatase and 1,25-dihydroxyvitamin D(3). Sequence analysis of the lymphocyte VDR cDNA revealed deletion mutation c.716delA. Sequence analysis of her genomic DNA fragment amplified from exon 6 of the VDR gene incorporating this mutation confirmed the presence of the mutation in homozygous form. This frameshift mutation in the ligand binding domain (LBD) resulted in premature termination (p.Lys240Argfs) of the VDR protein. The mutant protein contained 246 amino acids, with 239 normal amino acids at the N terminus, followed by seven changed amino acids resulting in complete loss of its LBD. The mutant VDR protein showed evidence of 50% reduced binding with VDR response elements on electrophoretic mobility assay in comparison to the wild-type VDR protein. She was treated with high-dose calcium infusion and oral phosphate. After 18 months of treatment, she gained 6 cm of height, serum calcium and phosphorus improved, alkaline phosphatase levels decreased, and intact PTH normalized. Radiologically, there were signs of healing of rickets. Her parents and one of her siblings had the same c.716delA mutation in heterozygous form. Despite the complete absence of LBD, the rickets showed signs of healing with intravenous calcium.
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Affiliation(s)
- Jeyaraman Kanakamani
- Department of Endocrinology and Metabolism, All India Institute of Medical Sciences, New Delhi 110029, India.
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Novakovic B, Sibson M, Ng HK, Manuelpillai U, Rakyan V, Down T, Beck S, Fournier T, Evain-Brion D, Dimitriadis E, Craig JM, Morley R, Saffery R. Placenta-specific methylation of the vitamin D 24-hydroxylase gene: implications for feedback autoregulation of active vitamin D levels at the fetomaternal interface. J Biol Chem 2009; 284:14838-48. [PMID: 19237542 PMCID: PMC2685665 DOI: 10.1074/jbc.m809542200] [Citation(s) in RCA: 184] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 02/20/2009] [Indexed: 11/21/2022] Open
Abstract
Plasma concentrations of biologically active vitamin D (1,25-(OH)(2)D) are tightly controlled via feedback regulation of renal 1alpha-hydroxylase (CYP27B1; positive) and 24-hydroxylase (CYP24A1; catabolic) enzymes. In pregnancy, this regulation is uncoupled, and 1,25-(OH)(2)D levels are significantly elevated, suggesting a role in pregnancy progression. Epigenetic regulation of CYP27B1 and CYP24A1 has previously been described in cell and animal models, and despite emerging evidence for a critical role of epigenetics in placentation generally, little is known about the regulation of enzymes modulating vitamin D homeostasis at the fetomaternal interface. In this study, we investigated the methylation status of genes regulating vitamin D bioavailability and activity in the placenta. No methylation of the VDR (vitamin D receptor) and CYP27B1 genes was found in any placental tissues. In contrast, the CYP24A1 gene is methylated in human placenta, purified cytotrophoblasts, and primary and cultured chorionic villus sampling tissue. No methylation was detected in any somatic human tissue tested. Methylation was also evident in marmoset and mouse placental tissue. All three genes were hypermethylated in choriocarcinoma cell lines, highlighting the role of vitamin D deregulation in this cancer. Gene expression analysis confirmed a reduced capacity for CYP24A1 induction with promoter methylation in primary cells and in vitro reporter analysis demonstrated that promoter methylation directly down-regulates basal promoter activity and abolishes vitamin D-mediated feedback activation. This study strongly suggests that epigenetic decoupling of vitamin D feedback catabolism plays an important role in maximizing active vitamin D bioavailability at the fetomaternal interface.
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Affiliation(s)
- Boris Novakovic
- Developmental Epigenetics, Murdoch Childrens Research Institute, Royal Children's Hospital, and Department of Paediatrics, University of Melbourne, Parkville, Victoria 3052, Australia
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