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Thompson KG, Dittmer KE, Blair HT, Fairley RA, Sim DFW. An outbreak of rickets in Corriedale sheep: Evidence for a genetic aetiology. N Z Vet J 2011; 55:137-42. [PMID: 17534417 DOI: 10.1080/00480169.2007.36757] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
CASE HISTORY A skeletal disease characterised by lameness, limb deformities and reduced growth rate occurred over two successive years in lambs born on a commercial sheep farm in Marlborough. A genetic aetiology was considered likely following exclusion of other known causes of rickets and because of the progressive nature of the disease, even after affected animals were transferred to another property. CLINICAL FINDINGS Affected lambs appeared normal at birth but developed clinical signs during the first 2 months of life. The most severely affected animals either died or were euthanised within the first year of life, but some survived to breeding age. Serum biochemistry revealed hypocalcaemia, hypophosphataemia and increased concentrations of 1,25 dihydroxyvitamin D. The mean serum 25 hydroxyvitamin D concentration was similar to that of control lambs. PATHOLOGICAL FINDINGS Gross lesions included enlarged costochondral junctions, bilateral irregularity of articular surfaces on humeral heads due to collapse of subchondral bone, thickened cortices in long bones and irregular thickening of physeal cartilages. Microscopically, tongues of hypertrophic chondrocytes extended from physes into metaphyseal regions; metaphyseal trabeculae were thick, disorganised and often lined by wide osteoid seams. Osteoclastic activity was excessive both in cortical and trabecular bone. DIAGNOSIS Inherited rickets in Corriedale sheep. CLINICAL RELEVANCE AND CONCLUSIONS: This disease is likely to be present in several Corriedale sheep flocks in New Zealand and may have been misdiagnosed as arthritis or other diseases causing lameness and/or poor growth. A defect in end-organ responsiveness to 1,25 dihydroxyvitamin D is the likely mechanism. This disease of sheep may be a useful model for studying vitamin D metabolism and the treatment of inherited forms of rickets in human beings.
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Abstract
This presentation introduces clinical aspects of hormone resistance through a number of case studies that illustrate how molecular defects at various steps in hormone production, signaling, or responsiveness can produce disease in humans. The presentation also shows how careful phenotyping of such patients has triggered decades of translational research.
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MESH Headings
- 3-Oxo-5-alpha-Steroid 4-Dehydrogenase/deficiency
- 3-Oxo-5-alpha-Steroid 4-Dehydrogenase/genetics
- Adolescent
- Alopecia/genetics
- Aquaporin 2/deficiency
- Aquaporin 2/genetics
- Calcium/therapeutic use
- Child
- Child, Preschool
- Disorder of Sex Development, 46,XY/enzymology
- Disorder of Sex Development, 46,XY/genetics
- Endocrine System Diseases/genetics
- Endocrine System Diseases/physiopathology
- Female
- Fibrous Dysplasia, Polyostotic/genetics
- Hormones/physiology
- Humans
- Male
- Mutation
- Phenotype
- Pseudohypoparathyroidism
- Receptor, Parathyroid Hormone, Type 1/deficiency
- Receptor, Parathyroid Hormone, Type 1/genetics
- Receptors, Calcitriol/deficiency
- Receptors, Calcitriol/genetics
- Rickets/classification
- Rickets/genetics
- Vitamin D/metabolism
- Vitamin D/therapeutic use
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Miedlich SU, Zhu ED, Sabbagh Y, Demay MB. The receptor-dependent actions of 1,25-dihydroxyvitamin D are required for normal growth plate maturation in NPt2a knockout mice. Endocrinology 2010; 151:4607-12. [PMID: 20685875 PMCID: PMC2946147 DOI: 10.1210/en.2010-0354] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Rickets is a growth plate abnormality observed in growing animals and humans. Rachitic expansion of the hypertrophic chondrocyte layer of the growth plate, in the setting of hypophosphatemia, is due to impaired apoptosis of these cells. Rickets is observed in humans and mice with X-linked hypophosphatemia that is associated with renal phosphate wasting secondary to elevated levels of fibroblast growth factor-23. Rickets is also seen in settings of impaired vitamin D action, due to elevated PTH levels that increase renal phosphate excretion. However, mice with hypophosphatemia secondary to ablation of the renal sodium-dependent phosphate transport protein 2a (Npt2a), have not been reported to develop rickets. Because activation of the mitochondrial apoptotic pathway by phosphate is required for hypertrophic chondrocyte apoptosis in vivo, investigations were undertaken to address this paradox. Analyses of the Npt2a null growth plate demonstrate expansion of the hypertrophic chondrocyte layer at 2 wk of age, with resolution of this abnormality by 5 wk of age. This is temporally associated with an increase in circulating levels of 1,25-dihydroxyvitamin D. To address whether the receptor-dependent actions of this steroid hormone are required for normalization of the growth plate phenotype, the Npt2a null mice were mated with mice lacking the vitamin D receptor or were rendered vitamin D deficient. These studies demonstrate that the receptor-dependent actions of 1,25-dihydroxyvitamin D are required for maintenance of a normal growth plate phenotype in the Npt2a null mice.
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Bockman RS. First it's rickets, then it's not the sodium-phosphate transporter 2a knockout mystery. Endocrinology 2010; 151:4599-601. [PMID: 20858767 DOI: 10.1210/en.2010-0818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Alzahrani AS, Zou M, Baitei EY, Alshaikh OM, Al-Rijjal RA, Meyer BF, Shi Y. A novel G102E mutation of CYP27B1 in a large family with vitamin D-dependent rickets type 1. J Clin Endocrinol Metab 2010; 95:4176-83. [PMID: 20534770 DOI: 10.1210/jc.2009-2278] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
CONTEXT Mutations in the CYP27B1 gene, which encodes vitamin D 1alpha-hydroxylase, are the genetic basis for vitamin D-dependent rickets type 1 (VDDR-I). OBJECTIVE The aim of this study was to investigate the CYP27B1 mutation in a large family with VDDR-I and characterize the genotype-phenotype correlation. PATIENTS AND METHODS The index patient was a 23-yr-old female who had a progressive form of rickets and growth retardation since the age of 9 months. Laboratory data showed hypocalcemia, low urine calcium, hypophosphatemia, high serum alkaline phosphatase, elevated PTH, and low serum 1,25-dihydroxyvitamin D(3). Her parents were healthy first-degree cousins, and two of her 12 siblings were affected with similar but milder rickets. Three other siblings were asymptomatic but had biochemical evidence of the disease. The entire coding region of the CYP27B1 gene was sequenced, and the mutation was characterized by functional studies. RESULTS We found a novel biallelic c.305G>A sequence variation at codon 102, changing amino acid from glycine to glutamic acid (G102E) in the patient and five affected siblings, whereas a monoallelic c.305G>A variation was present in the mother and five nonaffected siblings. This variation was not present in 100 population controls. Expression of this mutant in CHO cells revealed an 80% reduction in the 1alpha-hydroxylase activity as compared to wild-type activity. CONCLUSIONS A novel mutation in the CYP27B1 gene was found in patients with VDDR-I. This mutation resulted in a significant reduction in 1alpha-hydroxylase activity. The residual enzymatic activity may account for the mild phenotype presentation in some affected members.
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Ekpebegh CO, Blanco-Blanco E. Familial hypophosphataemic rickets affecting a father and his two daughters: a case report. West Afr J Med 2010; 29:271-274. [PMID: 20931517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
BACKGROUND Hypophosphataemic rickets (HR) is a rare cause of short stature associated with limb deformities. OBJECTIVE To report the clinical and laboratory features of HR in two siblings and their father. METHODS Following the diagnosis of HR in a 4-year-old girl, her siblings and parents were screened using clinical, laboratory, and radiological parameters. RESULTS Short stature, lower limb deformities, frontal bossing and hypophosphataemia were present in all three patients. Serum alkaline phosphatase (ALP) was markedly elevated in both siblings who were aged two and 11 years but only minimally raised in their 43-year-old father. While spontaneous mutation is the presumed aetiology in the father, X linked dominant inheritance is the likely cause in both daughters. CONCLUSIONS Hypophosphataemic rickets should be considered in the differential diagnosis of short stature associated with limb deformities regardless of a family history of HR. Serum ALP may not be remarkably elevated when the diagnosis is made in adulthood.
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Gong YG, Li YN, Zhang WH, Liu LJ, Kang XG. [Correlation between vitamin D receptor genetic polymorphism and 25-hydroxyvitamin D3 in vitamin D deficiency rickets]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2010; 12:544-546. [PMID: 20637153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
OBJECTIVE To study the correlation between vitamin D receptor genetic polymorphism Fokand vitamin D deficiency rickets in children between 1 to 3 years old, and to explore the significance of hereditary factors in the development of vitamin D deficiency rickets. METHODS Sixty-two children with vitamin D deficiency rickets and 60 healthy children as a control group were enrolled. Serum levels of 25-hydroxyvitamin D3 were measured using ELISA. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) genetic analysis method was used. A restriction fragment length polymorphism in the vitamin D receptor genetic polymorphism Fok I was tested. The frequencies of the vitamin D receptor genotype and allele were compared between the two groups. RESULTS Serum 25-hydroxyvitamin D3 levels in the rickets group were significantly lower than those in the control group ( 9.1+/-4.1 ng/mL vs 16.1+/-6.9 ng/mL; P<0.05 ). FF genotype in the vitamin D receptor genetic polymorphism Fok I was more common in the rickets group than in the control group (53% vs 25%; P<0.05). F allele frequency in the rickets group was significantly higher than that in the control group (73% vs 57%; P<0.05). CONCLUSIONS There is a correlation between vitamin D receptor genetic polymorphism Fok I and vitamin D deficiency rickets. This suggests that vitamin D receptor genetic polymorphism might play an important role in determining susceptibility to development of vitamin D deficiency rickets.
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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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Malloy PJ, Wang J, Srivastava T, Feldman D. Hereditary 1,25-dihydroxyvitamin D-resistant rickets with alopecia resulting from a novel missense mutation in the DNA-binding domain of the vitamin D receptor. Mol Genet Metab 2010; 99:72-9. [PMID: 19815438 PMCID: PMC2794978 DOI: 10.1016/j.ymgme.2009.09.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 09/09/2009] [Accepted: 09/09/2009] [Indexed: 10/20/2022]
Abstract
The rare genetic recessive disease, hereditary vitamin D resistant rickets (HVDRR), is caused by mutations in the vitamin D receptor (VDR) that result in resistance to the active hormone 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3) or calcitriol). In this study, we examined the VDR from a young boy with clinical features of HVDRR including severe rickets, hypocalcemia, hypophosphatemia and partial alopecia. The pattern of alopecia was very unusual with areas of total baldness, adjacent to normal hair and regions of scant hair. The child failed to improve on oral calcium and vitamin D therapy but his abnormal chemistries and his bone X-rays normalized with intravenous calcium therapy. We found that the child was homozygous for a unique missense mutation in the VDR gene that converted valine to methionine at amino acid 26 (V26M) in the VDR DNA-binding domain (DBD). The mutant VDR was studied in the patient's cultured skin fibroblasts and found to exhibit normal [(3)H]1,25(OH)(2)D(3) binding and protein expression. However, the fibroblasts were unresponsive to treatment with high concentrations of 1,25(OH)(2)D(3) as demonstrated by their failure to induce CYP24A1 gene expression, a marker of 1,25(OH)(2)D(3) responsiveness. We recreated the V26M mutation in the WT VDR and showed that in transfected COS-7 cells the mutation abolished 1,25(OH)(2)D(3)-mediated transactivation. The mutant VDR exhibited normal ligand-induced binding to RXRalpha and to the coactivator DRIP205. However, the V26M mutation inhibited VDR binding to a consensus vitamin D response element (VDRE). In summary, we have identified a novel V26M mutation in the VDR DBD as the molecular defect in a patient with HVDRR and an unusual pattern of alopecia.
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Ray D, Goswami R, Gupta N, Tomar N, Singh N, Sreenivas V. Predisposition to vitamin D deficiency osteomalacia and rickets in females is linked to their 25(OH)D and calcium intake rather than vitamin D receptor gene polymorphism. Clin Endocrinol (Oxf) 2009; 71:334-40. [PMID: 19094076 DOI: 10.1111/j.1365-2265.2008.03500.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Osteomalacia (OSM) and rickets are widely prevalent in developing countries especially in females. The factors associated with such predisposition are not known. OBJECTIVES To identify nutritional, endocrine and genetic factors related to calcium and vitamin D metabolism that are associated with OSM/rickets in females. SUBJECTS AND METHODS We studied 98 patients with OSM or rickets and their relatives including male and female sibs and parents (n = 221) for the presence of biochemical OSM {low serum 25-hydroxyvitamin D [25(OH)D], raised intact PTH (iPTH) and raised alkaline phosphatase} and associated nutritional and genetic factors. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) was used for genotyping vitamin D receptor (VDR) (BsmI and FokI) and PTH gene (BstBI and DraII) single nucleotide polymorphisms (SNPs) in 74 families. The differences in the factors associated with calcium and vitamin D among the different groups were analysed by analysis of variance (ANOVA). Logistic regression analysis and the transmission disequilibrium test (TDT) were carried out to assess association between nutritional and genetic factors, and the disease, respectively. RESULTS Most of the patients were female (91.8%). The mean serum 25(OH)D level of the female patients was comparable to that of the female sibs (14.4 +/- 5.7 vs. 18.3 +/- 9.7 nmol/l). The frequency of biochemical OSM was fivefold higher in female than in male sibs (24.4%vs. 4.9%). Female sibs also had significantly lower 25(OH)D, dietary calcium intake and sunshine exposure than male sibs. The frequency of biochemical OSM was comparable between mothers and fathers. The odds of biochemical OSM in the family members was reduced by 11% per 15-min daily sunshine exposure [odds ratio (OR) = 0.89, 95% confidence interval (CI) = 0.81-0.98, P = 0.02] and decreased by 20% per 100 mg dietary calcium intake (OR = 0.80, 95% CI = 0.67-0.96, P = 0.02). VDR/PTH gene SNPs showed no association with OSM/rickets on TDT analysis. CONCLUSION Among the immediate family members of patients with OSM/rickets, female sibs have features of biochemical OSM in up to 24.4%. Female sibs, unlike male sibs, share with patients features of markedly low serum 25(OH)D levels, poor dietary calcium intake and poor exposure to sunshine. Genetic factors such as VDR and PTH gene SNPs were not associated with OSM/rickets.
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Beck-Nielsen SS, Brock-Jacobsen B, Gram J, Brixen K, Jensen TK. Incidence and prevalence of nutritional and hereditary rickets in southern Denmark. Eur J Endocrinol 2009; 160:491-7. [PMID: 19095780 DOI: 10.1530/eje-08-0818] [Citation(s) in RCA: 189] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To estimate the incidence of nutritional rickets and the incidence and prevalence of hereditary rickets. DESIGN Population-based retrospective cohort study based on a review of medical records. METHODS Patients aged 0-14.9 years referred to or discharged from hospitals in southern Denmark from 1985 to 2005 with a diagnosis of rickets were identified by register search, and their medical records were retrieved. Patients fulfilling the diagnostic criteria of primary rickets were included. RESULTS We identified 112 patients with nutritional rickets of whom 74% were immigrants. From 1995 to 2005, the average incidence of nutritional rickets in children aged 0-14.9 and 0-2.9 years was 2.9 and 5.8 per 100,000 per year respectively. Among immigrant children born in Denmark, the average incidence was 60 (0-14.9 years) per 100,000 per year. Ethnic Danish children were only diagnosed in early childhood and the average incidence in the age group 0-2.9 years declined from 5.0 to 2.0 per 100,000 per year during 1985-1994 to 1995-2005. Sixteen cases of hereditary rickets were diagnosed during the study period giving an average incidence of 4.3 per 100,000 (0-0.9 years) per year. The prevalence of hypophosphatemic rickets and vitamin D-dependent rickets type 1 was 4.8 and 0.4 per 100,000 (0-14.9 years) respectively. CONCLUSIONS Nutritional rickets is rare in southern Denmark and largely restricted to immigrants, but the incidence among ethnic Danish children was unexpectedly high. Hereditary rickets is the most common cause of rickets in ethnic Danish children, but nutritional rickets is most frequent among all young children.
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Soni SS, Adikey GK, Raman AS. Vitamin D dependent rickets type II: late onset of disease and response to high doses of vitamin D. SAUDI JOURNAL OF KIDNEY DISEASES AND TRANSPLANTATION 2008; 19:796-798. [PMID: 18711299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
Vitamin D dependent rickets Type II is a rare autosomal recessive disorder. The disorder is characterized by end organ hyporesponsiveness to vitamin D. Common presentation of the disorder is total body alopecia and onset of rickets during the second half of the first year of life. Patients may display progressive rachitic bone changes, hypocalcemia and secondary hyper-parathyroidism. It is differentiated from vitamin D dependent rickets type I by virtue of response to physiological doses of exogenous vitamin D in the later. Target organ hyporesponsiveness can be overcome by higher doses of vitamin D or its analogues. We report a case of vitamin D dependent rickets type II with onset of rickets at the age of thirteen years without alopecia progressing to marked disability by twenty three years of age. She responded to massive doses of vitamin D with significant clinical improvement after six months of therapy.
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Abstract
Autosomal recessive hypophosphatemic rickets (ARHR), which is characterized by renal phosphate wasting, aberrant regulation of 1alpha-hydroxylase activity, and rickets/osteomalacia, is caused by inactivating mutations of dentin matrix protein 1 (DMP1). ARHR resembles autosomal dominant hypophosphatemic rickets (ADHR) and X-linked hypophosphatemia (XLH), hereditary disorders respectively caused by cleavage-resistant mutations of the phosphaturic factor FGF23 and inactivating mutations of PHEX that lead to increased production of FGF23 by osteocytes in bone. Circulating levels of FGF23 are increased in ARHR and its Dmp1-null mouse homologue. To determine the causal role of FGF23 in ARHR, we transferred Fgf23 deficient/enhanced green fluorescent protein (eGFP) reporter mice onto Dmp1-null mice to create mice lacking both Fgf23 and Dmp1. Dmp1(-/-) mice displayed decreased serum phosphate concentrations, inappropriately normal 1,25(OH)(2)D levels, severe rickets, and a diffuse form of osteomalacia in association with elevated Fgf23 serum levels and expression in osteocytes. In contrast, Fgf23(-/-) mice had undetectable serum Fgf23 and elevated serum phosphate and 1,25(OH)(2)D levels along with severe growth retardation and focal form of osteomalacia. In combined Dmp1(-/-)/Fgf23(-/-), circulating Fgf23 levels were also undetectable, and the serum levels of phosphate and 1,25(OH)(2)D levels were identical to Fgf23(-/-) mice. Rickets and diffuse osteomalacia in Dmp1-null mice were transformed to severe growth retardation and focal osteomalacia characteristic of Fgf23-null mice. These data suggest that the regulation of extracellular matrix mineralization by DMP1 is coupled to renal phosphate handling and vitamin D metabolism through a DMP1-dependent regulation of FGF23 production by osteocytes.
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Hollberg K, Marsell R, Norgård M, Larsson T, Jonsson KB, Andersson G. Osteoclast polarization is not required for degradation of bone matrix in rachitic FGF23 transgenic mice. Bone 2008; 42:1111-21. [PMID: 18346951 DOI: 10.1016/j.bone.2008.01.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Revised: 01/21/2008] [Accepted: 01/22/2008] [Indexed: 11/19/2022]
Abstract
Hypophosphatemic transgenic (tg) mice overexpressing FGF23 in osteoblasts display disorganized growth plates and reduced bone mineral density characteristic of rickets/osteomalacia. These FGF23 tg mice were used as an in vivo model to examine the relation between osteoclast polarization, secretion of proteolytic enzymes and resorptive activity. Tg mice had increased mRNA expression levels of the osteoblast differentiation marker Runx2 and mineralization-promoting proteins alkaline phosphatase and bone sialoprotein in the long bones compared to wild type (wt) mice. In contrast, expression of alpha1(I) collagen, osteocalcin, dentin matrix protein 1 and osteopontin was unchanged, indicating selective activation of osteoblasts promoting mineralization. The number of osteoclasts was unchanged in tg compared to wt mice, as determined by histomorphometry, serum levels of TRAP 5b activity as well as mRNA expression levels of TRAP and cathepsin K. However, tg mice displayed elevated serum concentrations of C-terminal telopeptide of collagen I (CTX) indicative of increased bone matrix degradation. The majority of osteoclasts in FGF23 tg mice lacked ultrastructural morphological signs of proper polarization. However, they secreted both cathepsin K and MMP-9 at levels comparable to osteoclasts with ruffled borders. Mineralization of bone matrix thus appears essential for inducing osteoclast polarization but not for secretion of osteoclast proteases. Finally, release of CTX by freshly isolated osteoclasts was increased on demineralized compared to mineralized bovine bone slices, indicating that the mineral component limits collagen degradation. We conclude that ruffled borders are implicated in acidification and subsequent demineralization of the bone matrix, however not required for matrix degradation. The data collectively provide evidence that osteoclasts, despite absence of ruffled borders, effectively participate in the degradation of hypomineralized bone matrix in rachitic FGF23 tg mice.
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Baroncelli GI, Bereket A, El Kholy M, Audì L, Cesur Y, Ozkan B, Rashad M, Fernández-Cancio M, Weisman Y, Saggese G, Hochberg Z. Rickets in the Middle East: role of environment and genetic predisposition. J Clin Endocrinol Metab 2008; 93:1743-50. [PMID: 18285415 DOI: 10.1210/jc.2007-1413] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT The Middle East has a high incidence of rickets, and it is also common in Europe-dwelling children of Middle Eastern origin. OBJECTIVE The objective of the study was to explore the mechanisms leading to rickets in children of the Middle East. DESIGN AND SETTING We conducted a prospective study in 98 rachitic and 50 controls (aged 6 months to 4 yr) from university and community outpatient hospitals in Egypt and Turkey. MAIN OUTCOME MEASURES We collected epidemiological, maternal, nutritional, radiographic, and biochemical parameters; markers of bone turnover; and vitamin D receptor (VDR) gene polymorphisms. RESULTS Epidemiological factors had a key role in pursuit of rickets; Egyptian and Turkish patients had lower (P < 0.01) dietary calcium intake than controls and the recommended dietary intakes, and serum 25-hydroxyvitamin D levels were reduced in patients, the difference with controls being significant (P < 0.001) only in Turkey, although rickets was more severe in Egypt as determined by the x-ray score (P < 0.05). In Turkey, the F VDR allele frequency was significantly (P < 0.05) increased in patients. The BB VDR genotype was associated with lower serum 25-hydroxyvitamin D levels in both patients and controls and with severity of rickets. CONCLUSIONS In Turkey most patients had vitamin D deficiency, whereas in Egypt they had mostly calcium insufficiency combined with vitamin D deficiency. In this environ, VDR genotypes may predispose to rickets by increased frequency of the F allele. The unique environs and genetic predisposition have to be accounted for in the design of preventive measures, rather than using European or American recommended dietary intake for calcium and vitamin D.
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Bora G, Ozkan B, Dayangaç-Erden D, Erdem-Yurter H, Coşkun T. Vitamin D receptor gene polymorphisms in Turkish children with vitamin D deficient rickets. Turk J Pediatr 2008; 50:30-33. [PMID: 18365588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Vitamin D deficient rickets is prevalent in Turkey and a considerable number of children are at risk of growth retardation, impaired bone formation and fracture. In order to check whether vitamin D receptor (VDR) gene polymorphism relates to the vitamin D deficient rickets, we analyzed VDR gene FokI, TaqI and ApaI polymorphisms in 24 Turkish vitamin D deficient rickets patients and 100 healthy controls. We found that "A" (ApaI) allele is more abundant in patients than controls (83 vs 57%, p = 0.002) but there were no significant differences for FokI (p = 0.693) and TaqI (p = 0.804) allele frequencies between patients and controls. We also showed that the frequency of Tt and Aa genotypes was significantly decreased in patients. Our results indicated that VDR gene polymorphisms might be an important factor for genetic susceptibility to vitamin D deficient rickets in the Turkish population.
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Fukumoto S. [Novel phosphate-regulating hormone, fibroblast growth factor (FGF) 23]. NIHON RINSHO. JAPANESE JOURNAL OF CLINICAL MEDICINE 2007; 65 Suppl 9:101-104. [PMID: 18161090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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Su JM, Li Y, Ye XW, Wu ZF. Oral findings of hypophosphatemic vitamin D-resistant rickets: report of two cases. Chin Med J (Engl) 2007; 120:1468-70. [PMID: 17825183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023] Open
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Kim CJ, Kaplan LE, Perwad F, Huang N, Sharma A, Choi Y, Miller WL, Portale AA. Vitamin D 1alpha-hydroxylase gene mutations in patients with 1alpha-hydroxylase deficiency. J Clin Endocrinol Metab 2007; 92:3177-82. [PMID: 17488797 DOI: 10.1210/jc.2006-2664] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Vitamin D 1alpha-hydroxylase deficiency, also known as vitamin D-dependent rickets type 1, is an autosomal recessive disorder characterized by the early onset of rickets with hypocalcemia and is caused by mutations of the 25-hydroxyvitamin D 1alpha-hydroxylase (1alpha-hydroxylase, CYP27B1) gene. The human gene encoding the 1alpha-hydroxylase is 5 kb in length, located on chromosome 12, and comprises nine exons and eight introns. We previously isolated the human 1alpha-hydroxylase cDNA and gene and identified 19 different mutations in 25 patients with 1alpha-hydroxylase deficiency. OBJECTIVES, PATIENTS, AND METHODS: We analyzed the 1alpha-hydroxylase gene of 10 patients, five from Korea, two from the United States, and one each from Argentina, Denmark, and Morocco, all from nonconsanguineous families. Each had clinical and radiographic features of rickets, hypocalcemia, and low serum concentrations of 1,25-dihydroxyvitamin D(3). RESULTS Direct sequencing identified the responsible 1alpha-hydroxylase gene mutations in 19 of 20 alleles. Four novel and four known mutations were identified. The new mutations included a nonsense mutation in exon 6, substitution of adenine for guanine (2561G-->A) creating a stop signal at codon 328; deletion of adenine in exon 9 (3922delA) causing a frameshift; substitution of thymine for cytosine in exon 2 (1031C-->T) causing the amino acid change P112L; and a splice site mutation, substitution of adenine for guanine in the first nucleotide of intron 7 (IVS7+1 G-->A) causing a frameshift. CONCLUSIONS Mutations in the 1alpha-hydroxylase gene previously were identified in 44 patients, to which we add 10 more. The studies show a strong correlation between 1alpha-hydroxylase mutations and the clinical findings of 1alpha-hydroxylase deficiency.
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Kaneko A, Urnaa V, Nakamura K, Kizuki M, Seino K, Inose T, Takano T. Vitamin D receptor polymorphism among rickets children in Mongolia. J Epidemiol 2007; 17:25-9. [PMID: 17202743 PMCID: PMC7058450 DOI: 10.2188/jea.17.25] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND It was reported that 32% of children under five years old in Mongolia had symptoms of rickets. Vitamin D receptor (VDR) gene polymorphism has received attention in relation to bone metabolism. We therefore investigated whether VDR polymorphism is related to high prevalence of rickets in Mongolia and to bone properties in childhood. METHODS We conducted a case-control study in Ulaanbaatar involving 80 children aged 7-10 years with a history of rickets (cases) and 72 children with no history of rickets (controls). VDR polymorphism was assessed using BsmI, ApaI, and TaqI, and bone properties were determined by measuring age-standardized midtibial cortical speed of sound (TCSOS). FINDINGS Each allelic frequency was verified to satisfy the Hardy-Weinberg equilibrium in cases, controls, and the total sample. The VDR polymorphisms among cases (BB 3%, Bb 18%, bb 80%; AA 15%, Aa 38%, aa 47%; and TT 81 %, Tt 17%, tt 3%) did not differ significantly from those among controls (BB 1%, Bb 13%, bb 86%; AA 16%, Aa 46%, aa 38%; and TT 86%, Tt 13%, tt 1%). There were no significant differences in TCSOS according to the VDR genotype among either cases or controls. CONCLUSIONS The VDR polymorphism does not play a major role in the development of rickets in Mongolia and has no effect on TCSOS in childhood.
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Kaji H. [Vitamin D-dependent rickets type I, II]. NIHON NAIKA GAKKAI ZASSHI. THE JOURNAL OF THE JAPANESE SOCIETY OF INTERNAL MEDICINE 2007; 96:737-41. [PMID: 17506313 DOI: 10.2169/naika.96.737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
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Lu JJ, Li YN, Jin Y, Li L. [Association of the vitamin D receptor gene start codon polymorphism with delayed rickets]. ZHONGHUA ER KE ZA ZHI = CHINESE JOURNAL OF PEDIATRICS 2007; 45:46-9. [PMID: 17349151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
OBJECTIVE Delayed rickets is a special type of vitamin D deficiency, the occurrences of delayed rickets mainly relate to vitamin D deficiency, but whether there is hereditary susceptibility of children to development of delayed rickets is unknown. Recently some studies suggest that there is a significant association between vitamin D receptor gene (VDR) polymorphism and the metabolic diseases of bone. The present study aimed to explore the hereditary susceptibility of children to development of delayed rickets through studying the association of the vitamin D receptor gene start codon (VDRSC) polymorphism with delayed rickets. METHODS The diagnosis was based on clinical, biochemical and radiological data. The subjects were composed of three groups, the patient group had 30 children, the vitamin D deficiency group 35 children, and the control group 60 normal children. The VDRSC genotypes of the three groups were determined by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. RESULTS There was significant difference in the frequencies distribution of VDRSC genotypes (chi(2) = 13.184, P = 0.010) and VDRSC alleles (chi(2) = 8.975, P = 0.011) among the three groups; the frequency of the FF genotype (56.7%) in the patient group was significantly higher than that in the control group (21.7%, P = 0.006) and that in the vitamin D deficiency group (22.9%, P = 0.002). The frequency of the F alleles in the patient group (70.0%) was significantly higher than that in the control group (48.3%, P = 0.006) and that in the vitamin D deficiency group (47.1%, P = 0.009). Multiple logistic regression analysis showed that FF genotype had a higher risk of delayed rickets (OR = 3.120), indicating that FF genotype may be significantly associated with delayed rickets. CONCLUSION There is the possibility that the VDRSC polymorphism might be important in determining the hereditary susceptibility of children to development of delayed rickets.
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Chen H, Hewison M, Adams JS. Functional Characterization of Heterogeneous Nuclear Ribonuclear Protein C1/C2 in Vitamin D Resistance. J Biol Chem 2006; 281:39114-20. [PMID: 17071612 DOI: 10.1074/jbc.m608006200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Clinically apparent hereditary vitamin D-resistant rickets (HVDRR) usually results from a loss of function mutation in the vitamin D receptor (VDR). We recently described a human with the classical HVDRR phenotype but normal VDR function. Hormone resistance resulted from constitutive overexpression of heterogeneous nuclear ribonucleoprotein (hnRNP) that competed with a normally functioning VDR-retinoid X receptor (RXR) dimer for binding to the vitamin D response element (VDRE). Here we describe the purification, molecular cloning, and expression of this vitamin D resistance-causing, competitive response element-binding protein (REBiP) hnRNP C1/C2. When overexpressed in vitamin D-responsive cells, cDNAs for both hnRNPC1 and hnRNPC2 inhibited VDR-VDRE-directed transactivation (28 and 43%, respectively; both p < 0.005). By contrast, transient expression of an hnRNP C1/C2 small interfering RNA increased VDR transactivation by 39% (p < 0.005). Chromatin immunoprecipitation of nucleoproteins bound to the transcriptionally active 1,25-dihydroxy vitamin D-driven CYP24 promoter revealed the presence of REBiP in vitamin D-responsive human cells and indicated that the normal pattern of 1,25-dihydroxy vitamin D-initiated cyclical movement of the VDR on and off the VDRE is legislated by competitive, reciprocal occupancy of the VDRE by hnRNP C1/C2. The temporal and reciprocal pattern of VDR and hnRNPC1/C2 interaction with the VDRE was lost in HVDRR cells overexpressing the hnRNP C1/C2 REBiP. These observations provide further evidence for the functional importance of REBiP as a component of the multiprotein complex involved in the regulation of vitamin D-mediated transcription. In particular, chromatin immunoprecipitation data suggest that, in addition to its RNA-processing functions, hnRNP C1/C2 may be a key determinant of the temporal patterns of VDRE occupancy.
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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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Feng JQ, Ward LM, Liu S, Lu Y, Xie Y, Yuan B, Yu X, Rauch F, Davis SI, Zhang S, Rios H, Drezner MK, Quarles LD, Bonewald LF, White KE. Loss of DMP1 causes rickets and osteomalacia and identifies a role for osteocytes in mineral metabolism. Nat Genet 2006; 38:1310-5. [PMID: 17033621 PMCID: PMC1839871 DOI: 10.1038/ng1905] [Citation(s) in RCA: 827] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Accepted: 09/18/2006] [Indexed: 12/20/2022]
Abstract
The osteocyte, a terminally differentiated cell comprising 90%-95% of all bone cells, may have multiple functions, including acting as a mechanosensor in bone (re)modeling. Dentin matrix protein 1 (encoded by DMP1) is highly expressed in osteocytes and, when deleted in mice, results in a hypomineralized bone phenotype. We investigated the potential for this gene not only to direct skeletal mineralization but also to regulate phosphate (P(i)) homeostasis. Both Dmp1-null mice and individuals with a newly identified disorder, autosomal recessive hypophosphatemic rickets, manifest rickets and osteomalacia with isolated renal phosphate-wasting associated with elevated fibroblast growth factor 23 (FGF23) levels and normocalciuria. Mutational analyses showed that autosomal recessive hypophosphatemic rickets family carried a mutation affecting the DMP1 start codon, and a second family carried a 7-bp deletion disrupting the highly conserved DMP1 C terminus. Mechanistic studies using Dmp1-null mice demonstrated that absence of DMP1 results in defective osteocyte maturation and increased FGF23 expression, leading to pathological changes in bone mineralization. Our findings suggest a bone-renal axis that is central to guiding proper mineral metabolism.
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