Abstract

ROLE OF VITAMIN D RECEPTOR (VDR) GENE POLYMORPHISM

Balwant Chauhan*and Prashant Sakharkar

ABSTRACT

Vitamin D deficiency leads to poor bone development and general health. The main source of vitamin D is dermal and amount synthesized depends upon exposure to sunlight. Additional amounts can also be obtained from food or through dietary supplementation. The inactive form of vitamin D is converted to its active form called calcitrol in liver and kidney, which is further utilized by variety of tissues, and its action is mediated via the vitamin D receptor (VDR). Newly converted calcitriol binds to the VDR protein, as encoded for by the VDR gene. VDR is expressed in most tissues of the body and there are several forms of VDR genes depicting polymorphism. There are four most common polymorphic forms found within the VDR gene are and these are referred as rs2228570, rs1544410, rs7975232 and rs731236. These are also known traditionally as FokI, BsmI, ApaI and TaqI, respectively. The role of polymorphic forms has been explored in recent years with genes linked to cardiovascular, autoimmune, humoral, pulmonary and neurological diseases. Inadequate levels of vitamin D in the body were found to be associated with various disorders such as Alzheimer, diabetes, heart disease, cancers etc. VDR gene polymorphism also found to influence the allograft outcomes in recipients of renal transplants. The goal of this review is to highlight the role of VDR gene polymorphism in especially in altering Bone Mass Density (BMD), degenerative disc disease, osteoporosis, rickets and other conditions such as breast cancer, allograft survival in renal transplant recipients, new onset diabetes at transplant, hepatitis B infection and chronic periodontitis. Results of the various studies discussed here will broaden our understanding of variability in the Vitamin D and might help us in assessing risk of the disease as a predictive marker and in predicting the treatment response.

Keywords: Vitamin D; vitamin D receptor; VDR gene; polymorphism; VDR gene polymorphism; allograft outcomes.