Navegando por Palavras-chave "vitamin D receptor polymorphism"

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    Fractures of the proximal femur: correlation with vitamin D receptor gene polymorphism
    (Associação Brasileira de Divulgação Científica, 1998-07-01) Ramalho, Ana Claudia [UNIFESP]; Lazaretti-Castro, Marise [UNIFESP]; Hauache, Omar Magid [UNIFESP]; Kasamatsu, Teresa Sayoko [UNIFESP]; Brandão, C.; Reis, André Fernandes [UNIFESP]; Takata, Edmilson Takehiro [UNIFESP]; Cafalli, Francisco [UNIFESP]; Tavares, F.; Gimeno, Suely Godoy Agostinho [UNIFESP]; Vieira, J.g.h.; A01; Universidade Federal de São Paulo (UNIFESP); Hospital do Servidor Público Estadual de São Paulo
    Fractures are the feared consequences of osteoporosis and fractures of the proximal femur (FPF) are those that involve the highest morbidity and mortality. Thus far, evaluation of bone mineral density (BMD) is the best way to determine the risk of fracture. Genetic inheritance, in turn, is one of the major determinants of BMD. A correlation between different genotypes of the vitamin D receptor (VDR) and BMD has been recently reported. On this basis, we decided to determine the importance of the determination of VDR genotype in the presence of an osteoporotic FPF in a Brazilian population. We studied three groups: group I consisted of 73 elderly subjects older than 65 years (78.5 ± 7.2 years) hospitalized for nonpathological FPF; group II consisted of 50 individuals older than 65 years (72.9 ± 5.2 years) without FPF and group III consisted of 98 young normal Brazilian individuals aged 32.6 ± 6.6 years (mean ± SD). Analysis of VDR gene polymorphism by restriction fragment length polymorphism (RFLP) was performed by PCR amplification followed by BsmI digestion of DNA isolated from peripheral leukocytes. The genotype distribution in group I was 20.5% BB, 42.5% Bb and 37% bb and did not differ significantly from the values obtained for group II (16% BB, 36% Bb and 48% bb) or for group III (10.2% BB, 47.6% Bb and 41.8% bb). No differences in genotype distribution were observed between sexes or between the young and elderly groups. We conclude that determination of VDR polymorphism is of no practical use for the prediction of FPF. Other nongenetic factors probably start to affect bone mass, the risk to fall and consequently the occurrence of osteoporotic fractures with advancing age.
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    Vitamin D receptor gene polymorphism and bone mineral density in hypercalciuric calcium-stone-forming patients
    (Karger, 2002-01-01) Heilberg, I. P.; Teixeira, S. H.; Martini, L. A.; Boim, M. A.; Universidade Federal de São Paulo (UNIFESP)
    Reduced bone mineral density (BMD) and an increased risk of vertebral fracture have been reported in calcium-stone-forming (CSF) patients presenting with idiopathic hypercalciuria. We investigated the association between Bsml vitamin D receptor (VDR) polymorphism and BMD in 68 hypercalciuric CSF patients (35 males and 33 premenopausal females, mean age +/- SD = 39 +/- 10 years). BMD was measured at lumbar spine (L-2-L-4) and femur neck sites using dual energy X-ray absorptiometry. A 72-hour dietary record and a 24-hour urine sample were obtained from each patient to determine calcium intake and excretion. the allelic frequency found for the sample as a whole was 16% BB, 44% Bb and 40% bb. Mean BMD values did not significantly differ among BB, Bb and bb patients at L2-L4 (1.162 +/- 0.10, 1.133 +/- 0.11 and 1.194 +/- 0.19 g/cm(2), mean SD, respectively) or at neck sites (0.920 +/- 0.11, 0.931 +/- 0.15 and 0.982 +/- 0.15 g/cm(2), respectively). Calcium intake and excretion were also not significantly different among the three genotypes. Patients were then divided into two groups, normal BMD, T-score greater than or equal to -1 (n = 34) and low BMD, T-score <-1 (n = 34), to further evaluate the allele influence on previous bone loss. Despite a trend for a higher mean BMD at spine or neck sites for patients with one or two b alleles when compared to BB patients, the difference did not reach statistical significance. the distribution of BB, Bb and bb genotypes in the low-bone-mass group (15, 47 and 38%, respectively) was similar to that in the normal-bone-mass group (18, 41 and 14%, respectively). These data suggest that Bsml VDR polymorphism does not play an important role in the bone loss seen in hypercalciuric CSF patients. Copyright (C) 2002 S. Karger AG, Basel.