[Study on the association of two polymorphisms of the vitamin D receptor (VDR) gene with the susceptibility to pulmonary tuberculosis (PTB) in Chinese Tibetans]

Abstract

Objective: To investigate the relationship between Fok I and Taq I polymorphisms of the VDR gene and the susceptibility of PTB in Chinese Tibetans.

Methods: Two polymorphisms of the VDR gene were typed by PCR-RFLP among 140 patients and 139 healthy controls who had been sensitized to tuberculosis. The relationship among two polymorphisms and the susceptibility of PTB were studied, and cases were grouped according to the genotypes.

Results: The genotype FF, Ff, ff were observed in 60, 56 and 24 cases among tuberculosis group while in 70, 60 and 9 cases among control group. A significant increase of VDR genotype ff (mutant homozygotes) was observed in the PTB patients when compared to controls (P < 0.05, OR 3.111, 95% confidence interval 1.343-7.207). The genotype of TT were in 137 cases, Tt in 3 cases among patients while TT in 134 cases , Tt in 5 cases among controls. No significant difference in these genotype frequencies was observed between two groups (P > 0.05, OR 1.704, 95% confidence interval 0.399-7.272). Two polymorphisms didn't show linkage disequilibrium and D' is 0.475.

Conclusion: The Fok I polymorphism of VDR gene might be associated with PTB in Chinese Tibetan population, but no evidences supported that the Taq I polymorphism were associated with PTB in Chinese Tibetan. The two polymorphisms didn't show linkage disequilibrium.