Abstract : Tuberculosisis a cosmopolitan disease caused by Mycobacterium tuberculosis. Even
within similar environmental conditions there is obvious variation in the incidence of this
disease which suggests genetic factor effects. This study aimed to assess the effect of vitamin
D receptorgene polymorphisms on the susceptibility for tuberculosis among Iraqi patients. A
total of 62 patients with tuberculosis and 48 apparently healthy controls were recruited for this
case/control study. DNA was extracted from peripheral blood, and vitamin D receptor gene
regions corresponding theFokI, BsmI and TaqI polymorphisms were amplified with specific
primers using PCR. Genotyping was achieved by restriction fragment length polymorphisms.
A significant association was found between homozygote mutant genotype of FokI (ff) and
susceptibility to TB (ff vs. FF: OR=10.452, 95%CI=1.253-87.167, P=0.03). Allele f of this
polymorphism was more prevalent among patients compared to controls (OR=3.333,
95%CI=1.635-6.797, P=0.001). On the other hand, allele t of TaqI polymorphism seems to
have a protective role against TB as it had significantly higher frequency in controls compared
to TB patients (OR=0.317, 95%CI=0.136-0.738, P=0.008). Therefore, the homozygote mutant
genotype of FokI could be considered as a risk factor for tuberculosis, while allele t of TaqI has
a protective role against the disease.