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Kashyap J, Kumari N, Ponnusamy K, Tyagi RK. Hereditary Vitamin D-Resistant Rickets (HVDRR) associated SNP variants of vitamin D receptor exhibit malfunctioning at multiple levels. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2023; 1866:194891. [PMID: 36396100 DOI: 10.1016/j.bbagrm.2022.194891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 10/11/2022] [Accepted: 11/02/2022] [Indexed: 11/16/2022]
Abstract
Vitamin D receptor (VDR) is a member of the nuclear receptor superfamily. It is a primary regulator of calcium and phosphate homeostasis required for skeleton and bone mineralization. Vitamin D in active form 1α,25 dihydroxyvitamin-D3 mediates its cellular functions by binding to VDR. Active VDR forms heterodimers with partner RXR (retinoid X receptor) to execute its physiological actions. HVDRR (Hereditary Vitamin D-Resistant Rickets) is a rare genetic disorder that occurs because of generalized resistance to the 1α,25(OH)2D3. HVDRR is caused by the polymorphic variations in VDR gene leading to defective intestinal calcium absorption and mineralization of newly forming bones. Using point and deletion SNPs of VDR we have studied several HVDRR-associated SNP variants for their subcellular dynamics, transcriptional functions, 'genome bookmarking', heterodimeric interactions with RXR, and receptor stability. We previously reported that VDR is a 'mitotic bookmarking factor' that remains constitutively associated with the mitotic chromatin to inherit 'transcriptional memory', however the mechanistic details remained unclear. We document that 'genome bookmarking' property by VDR is critically impaired by naturally occurring HVDRR-associated point and deletion variants found in patients. Furthermore, these HVDRR-associated SNP variants of VDR were found to be compromised in transcriptional function, nuclear translocation, protein stability and intermolecular interactions with its heterodimeric partner RXR. Intriguingly, majority of these disease-allied functional defects failed to be rescued by RXR. Our findings suggest that the HVDRR-associated SNP variations influence the normal functioning of the receptor, and this derived understanding may help in the management of disease with precisely designed small molecule modulators.
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Affiliation(s)
- Jyoti Kashyap
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | - Neha Kumari
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | | | - Rakesh K Tyagi
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India; Special Centre for Systems Medicine (Concurrent Faculty), Jawaharlal Nehru University, New Delhi 110067, India.
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Tsai SY, Catts VS, Fullerton JM, Corley SM, Fillman SG, Weickert CS. Nuclear Receptors and Neuroinflammation in Schizophrenia. MOLECULAR NEUROPSYCHIATRY 2018; 3:181-191. [PMID: 29888229 DOI: 10.1159/000485565] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 11/21/2017] [Indexed: 01/23/2023]
Abstract
Introduction Several nuclear receptor family members have been associated with schizophrenia and inflammation. Vitamins A and D exert anti-inflammatory actions, but their receptors (mainly nuclear receptors) have not been extensively studied in either schizophrenia brains or in association with neuroinflammation. We examined the expression of vitamin A (RARs and RXRs) and vitamin D and protein disulphide-isomerase A3 (PDIA3) receptors, as well as nuclear orphan receptors (NR4As), in the context of elevated cytokine expression in the dorsolateral prefrontal cortex (DLPFC). Methods mRNA levels of nuclear receptors were measured in DLPFC tissues via RT-qPCR. ANCOVAs comparing high inflammation schizophrenia, low inflammation schizophrenia and low inflammation control groups were performed. Results RARG, RXRB, NR4A1 and NR4A3 transcripts showed significant differential expression across the three groups (ANCOVA p = 0.02-0.001). Post hoc testing revealed significant reductions in RARG expression in schizophrenia with low inflammation compared to schizophrenia with high inflammation and to controls, and RXRB mRNA was significantly reduced in schizophrenia with low inflammation compared to controls. NR4A1 and NR4A3 mRNAs were decreased in schizophrenia with high inflammation compared to schizophrenia with low inflammation, with NR4A1 also significantly different to controls. Conclusion In schizophrenia, changes in nuclear receptor mRNA levels involved with mediating actions of vitamin A derivatives vary according to the inflammatory state of brains.
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Affiliation(s)
- Shan-Yuan Tsai
- Schizophrenia Research Institute, Sydney, New South Wales, Australia.,Neuroscience Research Australia, Sydney, New South Wales, Australia.,School of Psychiatry, University of New South Wales, Sydney, New South Wales, Australia
| | - Vibeke S Catts
- Schizophrenia Research Institute, Sydney, New South Wales, Australia.,Neuroscience Research Australia, Sydney, New South Wales, Australia.,School of Psychiatry, University of New South Wales, Sydney, New South Wales, Australia
| | - Janice M Fullerton
- Schizophrenia Research Institute, Sydney, New South Wales, Australia.,Neuroscience Research Australia, Sydney, New South Wales, Australia.,School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Susan M Corley
- Systems Biology Initiative, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Stuart G Fillman
- Schizophrenia Research Institute, Sydney, New South Wales, Australia.,Neuroscience Research Australia, Sydney, New South Wales, Australia.,School of Psychiatry, University of New South Wales, Sydney, New South Wales, Australia
| | - Cynthia Shannon Weickert
- Schizophrenia Research Institute, Sydney, New South Wales, Australia.,Neuroscience Research Australia, Sydney, New South Wales, Australia.,School of Psychiatry, University of New South Wales, Sydney, New South Wales, Australia
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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: 0.6] [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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Hereditary 1,25-dihydroxyvitamin D-resistant rickets (HVDRR) caused by a VDR mutation: A novel mechanism of dominant inheritance. Bone Rep 2015; 2:68-73. [PMID: 28377956 PMCID: PMC5365159 DOI: 10.1016/j.bonr.2015.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 05/06/2015] [Indexed: 02/01/2023] Open
Abstract
Hereditary 1,25-dihydroxyvitamin D-resistant rickets (HVDRR) is caused by mutations in the VDR gene, and its inheritance is autosomal recessive. In this report, we aimed to confirm whether HVDRR is occasionally inherited as a dominant trait. An 18-month-old Japanese boy was evaluated for short stature and bowlegs. His father had been treated for rickets during childhood, and his paternal grandfather had bowlegs. We diagnosed him with HVDRR based on laboratory data and radiographic evidence of rickets. Sequence analyses of VDR were performed, and the functional consequences of the detected mutations were analyzed for transcriptional activity, ligand binding, and interaction with the retinoid X receptor, cofactors, and the vitamin D response element (VDRE). A novel mutation (Q400LfsX7) and a reported variant (R370H) were identified in the patient. Heterozygous Q400LfsX7 was detected in his father, and heterozygous R370H was detected in his healthy mother. Functional studies revealed that the transcriptional activity of Q400LfsX7-VDR was markedly disturbed. The mutant had a dominant-negative effect on wild-type-VDR, and the ligand binding affinity of Q400LfsX7-VDR was completely impaired. Interestingly, Q400LfsX7-VDR had a strong interaction with corepressor NCoR and could interact with VDRE without the ligand. R370H-VDR was functionally similar to wild-type-VDR. In conclusion, we found a dominant-negative mutant of VDR causing dominantly inherited HVDRR through a constitutive corepressor interaction, a mechanism similar to that in dominantly inherited thyroid hormone receptor mutations. Our report together with a reported pedigree suggested a distinct inheritance of HVDRR and enriched our understanding of VDR abnormalities. We report the pedigree of dominantly inherited hereditary vitamin D resistant rickets. A novel VDR mutation (Q400LfsX7) was identified in the pedigree. The mutant had a dominant-negative effect on the wild type VDR and interacted strongly with corepressor NCoR. The mechanism for dominantly inheritance was similar to that in dominantly inherited thyroid hormone receptor mutations.
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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: 25] [Impact Index Per Article: 2.5] [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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Normal vitamin D receptor function with increased expression of 25-hydroxyvitamin D3-24-hydroxylase in Corriedale sheep with inherited rickets. Res Vet Sci 2011; 91:362-9. [DOI: 10.1016/j.rvsc.2010.09.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 08/30/2010] [Accepted: 09/23/2010] [Indexed: 01/08/2023]
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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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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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Kalueff AV, Lou YR, Laaksi I, Tuohimaa P. ABNORMAL BEHAVIORAL ORGANIZATION OF GROOMING IN MICE LACKING THE VITAMIN D RECEPTOR GENE. J Neurogenet 2009; 19:1-24. [PMID: 16076629 DOI: 10.1080/01677060590949683] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Vitamin D is a steroid hormone with several important functions in the nervous system. Numerous human and animal data link alterations in the vitamin D system to various behavioral disorders. Grooming is an important element of rodent behavior with a general pattern of cephalocaudal progression (paw licking - nose/face wash - body wash - tail/genitals wash). Here we studied whether genetic ablation of vitamin D nuclear receptors (VDR) in mice may be associated with altered behavioral sequencing of grooming. Overall, VDR null mutant mice showed abnormal grooming, including a higher percentage of "incorrect" transitions and longer duration of "incorrect" grooming (contrary to the cephalocaudal progression); a higher percentage of interrupted grooming bouts; and the atypical regional distribution of grooming (more leg grooming, less body and tail/genitals grooming), compared to their wild-type controls. Grooming of heterozygous mice was similar to the wild-type group, indicating that abnormal grooming patterning is inherited as a recessive. In contrast, behavioral sequencing of another complex behavior (mating with a female) was unaltered in all three genotypes, suggesting grooming-specific abnormal sequencing in these mutant mice. Our results suggest that a neurosteroid vitamin D and VDR may play an important role in controlling sequencing of grooming in mice, and further confirm the important role of the vitamin D system and VDR in the regulation of behavior.
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Affiliation(s)
- Allan V Kalueff
- Department of Anatomy, Medical School, University of Tampere, Tampere, Finland.
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Abstract
Hereditary vitamin D receptor defects (HVDRDs) is a more appropriate and precise title for an inborn error of metabolism commonly known as pseudo-vitamin D deficiency or vitamin D dependency, type II. It is a rare autosomal recessive disorder, approximately 70 kindreds were described, but its main importance is elucidating the physiology of vitamin D and calcium homeostasis in humans. Patients usually develop the clinical and biochemical aberrations, identical to vitamin D deficiency, but with high serum levels of calcitriol, within the first year of life (i.e., muscle weakness, bone pain, deformities, and fractures). Defective calcium gut absorption leads to hypocalcemia, secondary hyperparathyroidism, hypophosphatemia, and defective mineralization of newly formed bone matrix. The disease is not cured by vitamin D replacement therapy, although some patients respond to very high doses of vitamin D or its metabolites. Cells derived from patients, mainly cultured skin fibroblasts, were used to assess steps in calcitriol action from cellular uptake to bioresponse and to elucidate the molecular aberrations in the vitamin D receptor (VDR). Point mutations in the VDR gene were identified in every patient examined, and the same defect was observed in the obligatory heterozygotes. The functional characterization of the patient's VDR reflected the localization of the mutation (18 different ones described to date), thus providing vital information about the structure-function relationship in the human VDR and the essentiality of the VDR as the mediator of vitamin D action.
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Arita K, Nanda A, Wessagowit V, Akiyama M, Alsaleh QA, McGrath JA. A novel mutation in the VDR gene in hereditary vitamin D-resistant rickets. Br J Dermatol 2007; 158:168-71. [PMID: 17970811 DOI: 10.1111/j.1365-2133.2007.08232.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- K Arita
- Genetic Skin Disease Group, St John's Institute of Dermatology, Division of Genetics and Molecular Medicine, The Guy's, King's College and St Thomas' School of Medicine, London, UK.
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Nicolaidou P, Papadopoulou A, Matsinos YG, Georgouli H, Fretzayas A, Papadimitriou A, Priftis K, Douros K, Chrousos GP. Vitamin D Receptor Polymorphisms in Hypocalcemic Vitamin D-Resistant Rickets Carriers. Horm Res Paediatr 2006; 67:179-83. [PMID: 17106204 DOI: 10.1159/000097014] [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: 02/13/2006] [Accepted: 09/21/2006] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND/AIMS Hypocalcemic vitamin D-resistant rickets (HVDRR) is a rare autosomal recessive disorder characterized by severe rickets, hypocalcemia, secondary hyperparathyroidism, elevated levels of 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)], and occasionally, alopecia. In most cases, the disease is associated with mutations in the gene of the vitamin D receptor (VDR), the mediator of 1,25(OH)(2)D(3) action. The apparently healthy HVDRR heterozygotes express both normal and mutant VDR alleles, and they present higher levels of 1,25(OH)(2)D(3) than their respective controls. Because VDR function, except for the disease-causative mutations, might be influenced by the presence of certain polymorphisms, we investigated the distribution of four common VDR polymorphisms--BsmI, ApaI, TaqI and FokI--in HVDRR carriers compared with their respective controls. METHODS Sixty-seven relatives of 2 HVDRR patients, all members of an extended Greek kindred, were included in the study. VDR allelic polymorphisms were assessed by restriction fragment length polymorphisms after specific polymerase chain reaction amplification. RESULTS The distribution of genotypic and allelic frequencies differed between HVDRR carriers and their respective controls regarding BsmI and TaqI polymorphisms. The bb genotype and the T allele (presence of BsmI and absence of TaqI polymorphisms) were less frequent in the HVDRR carrier group than in the control group in a statistically significant manner (p = 0.029 and p = 0.025, respectively). CONCLUSIONS Our findings showed that the apparently healthy HVDRR carriers present a different distribution of BsmI and TaqI VDR polymorphisms than their controls, suggesting that further investigation of the HVDRR carrier population may elucidate the implication of VDR alleles in VDR function and the vitamin D endocrine system.
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Affiliation(s)
- Polyxeni Nicolaidou
- Third Department of Pediatrics, University General Hospital Attikon, Athens University Medical School, Chaidari, Greece.
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Malloy PJ, Wang J, Peng L, Nayak S, Sisk JM, Thompson CC, Feldman D. A unique insertion/duplication in the VDR gene that truncates the VDR causing hereditary 1,25-dihydroxyvitamin D-resistant rickets without alopecia. Arch Biochem Biophys 2006; 460:285-92. [PMID: 17078924 PMCID: PMC1892178 DOI: 10.1016/j.abb.2006.09.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 09/27/2006] [Accepted: 09/29/2006] [Indexed: 11/26/2022]
Abstract
Hereditary vitamin D resistant rickets (HVDRR) is caused by mutations in the vitamin D receptor (VDR). Here we describe a patient with HVDRR who also exhibited some hypotrichosis of the scalp but otherwise had normal hair and skin. A 102 bp insertion/duplication was found in the VDR gene that introduced a premature stop (Y401X). The patient's fibroblasts expressed the truncated VDR, but were resistant to 1,25(OH)2D3. The truncated VDR weakly bound [3H]-1,25(OH)2D3 but was able to heterodimerize with RXR, bind to DNA and interact with the corepressor hairless (HR). However, the truncated VDR failed to bind coactivators and was transactivation defective. Since the patient did not have alopecia or papular lesions of the skin generally found in patients with premature stop mutations this suggests that this distally truncated VDR can still regulate the hair cycle and epidermal differentiation possibly through its interactions with RXR and HR to suppress gene transactivation.
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Affiliation(s)
- Peter J Malloy
- Division of Endocrinology, Gerontology and Metabolism, Department of Medicine, Stanford University School of Medicine, Stanford University Medical Center, Stanford, CA 94305, USA.
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Katavetin P, Katavetin P, Wacharasindhu S, Shotelersuk V. A girl with a novel splice site mutation in VDR supports the role of a ligand-independent VDR function on hair cycling. HORMONE RESEARCH 2006; 66:273-6. [PMID: 16946620 DOI: 10.1159/000095546] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Accepted: 06/20/2006] [Indexed: 11/19/2022]
Abstract
Mutations in vitamin D receptor (VDR) cause hereditary vitamin D resistant rickets (HVDRR). We reported a Thai girl with HVDRR, presenting with an early onset of rickets and partial alopecia. She was a product of a consanguineous couple. Mutation analysis showed that she was homozygous for a novel splice site mutation of the VDR gene, 462 + 1 G --> C, resulting in incorporation of the whole 254 bp of the intron 4 into its mRNA. The mutated protein is expected to contain no ligand-binding domain. The fact that she did not develop total alopecia despite of no VDR ligand-binding domain supports that VDR function on hair cycling is ligand independent.
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Affiliation(s)
- Paravee Katavetin
- Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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Nguyen M, d'Alesio A, Pascussi JM, Kumar R, Griffin MD, Dong X, Guillozo H, Rizk-Rabin M, Sinding C, Bougnères P, Jehan F, Garabédian M. Vitamin D-resistant rickets and type 1 diabetes in a child with compound heterozygous mutations of the vitamin D receptor (L263R and R391S): dissociated responses of the CYP-24 and rel-B promoters to 1,25-dihydroxyvitamin D3. J Bone Miner Res 2006; 21:886-94. [PMID: 16753019 DOI: 10.1359/jbmr.060307] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED We report here the first association between vitamin D-resistant rickets, alopecia, and type 1 diabetes in a child with compound heterozygous mutations in the VDR gene. Transfection studies suggest dissociated effects of VDR gene mutations on the regulation of genes involved in vitamin D metabolism and dendritic cell maturation. INTRODUCTION Whereas vitamin D may play a role in the immune tolerance process, no patient has been reported to associate hereditary vitamin D-resistant rickets (HVDRR) and an autoimmune disease, and no attempt has been made to delineate the outcome of mutations of the vitamin D receptor (VDR) on the transcription of genes controlling immune tolerance. MATERIALS AND METHODS The VDR gene was analyzed in a child with vitamin D-resistant rickets, total alopecia, and early childhood-onset type 1 diabetes. Patient's fibroblasts and COS-7 cells transfected with wildtype or mutant VDRs were studied for ligand-binding capacity, transactivation activity using two gene promoters [CYP-24, a classical 1,25(OH)2D3-responsive gene, and relB, a critical NF-kappaB component for regulation of dendritic cell differentiation], VDR-RXR heterodimers association to CYP 24 VDREs by gel mobility shift assays, and co-activator binding by Glutathione-S-transferase pull-down assays. RESULTS Two novel compound heterozygous mutations (L263R and R391S) were identified in the VDR ligand-binding domain in this child. Both mutations significantly impaired VDR ligand-binding capacity but had dissociated effects on CYP-24 and RelB promoter responses to vitamin D. CYP 24 response binding to SRC-1 and RXR-heterodimer binding to CYP24 VDREs were abolished in L263R mutants but normal or partially altered in R391S mutants. In the opposite, RelB responses to vitamin D were close to normal in L263R mutants but abolished in R391S mutants. CONCLUSIONS We report the first clinical association between HVDRR, total alopecia, and early childhood-onset type 1 diabetes. Mutations in the VDR ligand-binding domain may hamper the 1,25(OH)2D3-mediated relB responses, an effect that depends on the site of the VDR mutation and cannot be anticipated from VDR ligand-binding ability or CYP-24 response. Based on these results, we propose to survey the immune function in patients with HVDRR, including those with moderate features of rickets.
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MESH Headings
- Animals
- Calcitriol/pharmacology
- Cells, Cultured
- Child, Preschool
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/genetics
- Fibroblasts/drug effects
- Fibroblasts/enzymology
- France
- Gene Amplification
- Genome
- Humans
- Hypophosphatemia, Familial/complications
- Hypophosphatemia, Familial/genetics
- Male
- Mutation
- Promoter Regions, Genetic/drug effects
- Receptors, Calcitriol/genetics
- Receptors, Calcitriol/metabolism
- Sequence Analysis, DNA
- Steroid Hydroxylases/genetics
- Transcription Factor RelB/genetics
- Vitamin D3 24-Hydroxylase
- White People/genetics
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Affiliation(s)
- Minh Nguyen
- INSERM Unité 561, Hôpital St Vincent de Paul, Paris, France.
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Nicolaidou P, Papadopoulou A, Georgouli H, Matsinos YG, Tsapra H, Fretzayas A, Giannoulia-Karantana A, Kitsiou S, Douros K, Papassotiriou I, Chrousos GP. Calcium and vitamin D metabolism in hypocalcemic vitamin D-resistant rickets carriers. HORMONE RESEARCH 2006; 65:83-8. [PMID: 16424674 DOI: 10.1159/000091043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Accepted: 12/01/2005] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS Hypocalcemic vitamin D-resistant rickets (HVDRR) is a rare monogenic autosomal recessive disorder associated with mutations in the gene of the vitamin D receptor (VDR), the mediator of 1,25(OH)2D3 action. Although many investigations have discussed the clinical manifestations and molecular etiology of this disease, only a few have investigated the biochemical and hormonal status of heterozygous HVDRR. The aim of the current work was to investigate the profile of selected biochemical and hormonal parameters related to the vitamin D endocrine system in a large number of HVDRR heterozygotes. METHODS 67 relatives of 2 HVDRR patients, all members of an extended Greek kindred of five generations with a common ancestor, were included in the study. Direct sequencing was used to identify VDR gene mutations. Serum Ca, P, 25(OH)D, iPTH, and 1,25(OH)2D levels were determined in all members of the kindred. RESULTS DNA analysis of the participants led to the design of two study groups: the HVDRR carriers (24) and the control subjects (43). Our results showed elevated circulating serum levels of 1,25(OH)2D3 and lower levels of PTH than their age- and sex-matched controls. No hypocalcemia or hypophosphatemia were detected in HVDRR carriers. CONCLUSIONS Our findings suggest that HVDRR carriers may have compensatory elevated serum levels of 1,25(OH)2D3 through which they restrain PTH secretion. The study of HVDRR carriers could be a useful tool for the investigation of the vitamin D endocrine system.
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Affiliation(s)
- Polyxeni Nicolaidou
- Third Department of Pediatrics, Athens University Medical School, University General Hospital Attikon, Chaidari, Greece.
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