Vitamin D binding protein rs7041 and rs4588 gene polymorphisms in Ugandan tuberculosis patients and household contacts: A pilot study

Background Tuberculosis remains a significant global public health concern. Genetic variants influence the distribution of vitamin D in circulation, leading to vitamin D deficiency. The two extensively studied non-synonymous D-binding protein nucleotide polymorphisms rs7041 and rs4588 were found in different populations. These polymorphisms result into three different genotypes, Gc1F (rs7041(A)- rs4588(G)), Gc1S (rs7041(C)- rs4588(G)) and Gc2 (rs7041(A)- rs4588(T)). These genotypes have configurational changes that differ and therefore cause variation in the binding affinity of the vitamin D metabolite. This study aimed to compare the frequency distribution of vitamin D binding protein gene polymorphisms in patients with active Ugandan tuberculosis, individuals with latent tuberculosis infection, and those with no tuberculosis infection. Methods This pilot studyselected 102 samples, including 52 active tuberculosis patients, 23 latent tuberculosis individuals, and 27 individuals without tuberculosis infection, from a previous cross-sectional study. Vitamin D binding protein rs7041 and rs4588 SNPs were genotyped using Polymerase Chain Reaction and Sanger sequencing. Vitamin D binding protein gene polymorphisms were identified using BioEdit software. 7.2 (http://www.mbio.ncsu.edu/BioEdit/bioedit.html) Results This study revealed no significant differences in DBP genetic polymorphisms among the study groups. The frequency distribution of the DBP gene has been reported to be 97% Gc1F, 2% Gc2, and 1% Gc1S. The frequency distribution among patients with TB was 96.2% for Gc1F, 0% for Gc1F, and 3.8% for Gc2. Among the LTBI cases, 95.7% were Gc1F, 4.3% were Gc1S, and 0%were Gc2. The Hardy-Weinberg equilibrium analysis was in equilibrium, D’= 0. P=0.2 Conclusions The Gc1F genotype was predominantly found in the study population, with no difference in the frequency distribution according to TB status.