Investigation of the association between pterygium and TRPM channel gene polymorphisms

Pterygium is a common ocular surface disease characterized by epithelial and fibrovascular outgrowth of conjunctiva over the cornea. However, the exact mechanisms of pterygium formation are still unknown. Transient receptor potential (TRP) channels are a highly diverse group of ion channels with widely diverging functional properties. The hypothesis that TRP melastatin (TRPM) gene polymorphisms may play a role in pterygium development is examined in this study. The aim of this research is to investigate the association of TRPM gene polymorphisms and pterygium in Turkish population. A total of 48 pterygium patients and 48 healthy subjects (control group) with similar age and gender were enrolled in this study. Genomic DNA was isolated from peripheral leukocyte and 41 TRPM gene polymorphisms were identified by using BioMark HD dynamic array system with real-time PCR. Genotype and allele frequencies were evaluated with chi-square or Fisher's exact tests, and haplotypes were analysed with SHEsis programme. Genotype and allele distributions of TRPM5 rs2301699, TRPM5 rs886277 (Asn235Ser), and TRPM7 rs8042919 (Thr1482Ile) polymorhisms were found to be significantly associated with pterygium. Haplotypes based on the TRPM5 gene polymorphisms were constructed, and two haplotypes (CC and GT) with significant associations with pterygium were detected. No associations were found with other polymorphisms studied. Our results are the first to demonstrate that there is significant association between pterygium and TRPM5 and TRPM7 gene polymorphisms in Turkish population. Our data suggest that the presence of TRPM5 and TRPM7 gene variants can be a risk factor for the pterygium development.