<p><b>OBJECTIVE</b>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.</p><p><b>
METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>There is the possibility that the VDRSC polymorphism might be important in determining the hereditary susceptibility of
children to development of delayed
rickets.</p>