Association between variants on the vitamin D Receptor gene and chronic kidney disease among a Yoruba population in Ibadan, Nigeria

Chronic kidney disease, characterized by progressive loss of kidney function is a disease of public health importance globally. The burden is on a steep rise in Nigeria and sub-Saharan Africa, thereby contributing to the double epidemic of communicable and non-communicable diseases in this region of the world. Genome-wide association studies have identified several variants on different genes including the Vitamin D receptor (VDR) gene, associated with CKD defining traits. This study evaluated the association between SNPs on the VDR gene rs4334089 (CviAll), rs1544410 (BsmI) and rs7975232 (ApaI) with CKD in a Yoruba population of Nigeria. This case-control study recruited a total of 203 participants. Variants were amplified and genotyped using PCR-RFLP. Genotypes were tested for conformity with the Hardy-Weinberg equilibrium and associations were tested under three inheritance patterns. Results showed the minor allelic frequency of rs1544410 (BsmI) differed significantly from the reference value for the Nigerian population as reported on 1000 Genomes database. We report for the first time the relationship between vitamin D receptor polymorphisms, (rs4334089 (CviAll), rs1544410 (BsmI) and rs7975232 (ApaI) and chronic kidney disease in a Yoruba population from Ibadan southwest Nigeria. We found a significant risk association of CviAII with CKD under the dominant inheritance model (OR = 5.29; p = 7.13e-8), while CviAII was associated with protection to CKD under the recessive inheritance model (OR = 0.04; p = 0.002). This study provides further evidence that vitamin D receptor gene polymorphisms contribute to the risk chronic kidney disease in the Ibadan southwest population.