Abstract :
Introduction: Polymorphism in Vitamin D binding protein (DBP) has been implicated as one of the causes
for Vitamin D deficiency. However there is paucity of data regarding the effect of genetic polymorphism
in DBP in Vitamin D deficient patients in our population. This pilot study was undertaken to analyze
the common genetic polymorphism in vitamin DBP in these population and its effect on vitamin D
supplementation.
Materials and Methods: 80 vitamin D deficient subjects were selected by convenient sampling. Genetic
analysis for DBP (GC) gene polymorphism (rs7041 rs4588) was carried out in all these individuals after
informed consent and correlated with the vitamin D levels post supplementation.
Results: Six combinations of genotype were obtained (rs7041 rs4588): TT CA, TG CC, TT CA,
TT CC, TT AA, GG CC. A third of all individuals (33%) were found to have the TG CA genotype,
followed by about 26 % of individuals having the GG CC genotype. TT CA group was found to have
13% individuals and a tenth of all individuals belonged to each of the groups with TG CC and TT AA
genotypes. Least proportion of individuals was found to have the TT CA genotype (6%). There was no
significant difference in the vitamin D levels with individual polymorphism (p value the combined genotype had an effect, with homozygotes for both such as TT-CC, TT-AA showing least
response and heterozygotes such TG-CA and CG-CC showing better response
Discussion and Conclusion: In this study, the individual SNP (rs7041 and rs4588) did not seem to
significantly influence the response to vitamin D supplementation. However the combined genotype seem
ed to influence the proportion of patients showing improvement after supplementation. The homozygotes
for both such as TT-CC, TT-AA showing least response and heterozygotes such TG-CA and CG-CC
showing better response.
Keyword :
Vitamin D, SNP, rs7041, rs4588.