The susceptibility to diabetic retinopathy in type 2 diabetic patients of Iran is not affected by the M55V polymorphism of SUMO4

Abstract

Introduction: Recent reports showed that the small ubiquitin-like modifier 4 (SUMO4) M55V polymorphism is affected development of type 2 diabetes and its complications such as diabetic nephropathy and retinopathy in some populations. In this regard we intend to investigate the impact of M55V polymorphism of SUMO4 on susceptibility to diabetic retinopathy in the type 2 diabetic patients of Iran. Methods: In current study, the control group had included 100 individuals of type 2 diabetic patients of Iran who have not retinopathy, while the patient group had included 100 individuals of type 2 diabetic patients of Iran suffering from retinopathy. We have matched all the confounding factors between patients and controls. The genotyping method was PCR-RFLP to trace a prevalent single nucleotide polymorphism at codon 55 encoding a substitution of methionine to valine (M55V) specified in the SUMO4 gene. Results: Genotype frequency of AA, AG, and GG of SUMO4 were obtained respectively 52, 30, and 18 in the patient group and 44, 36, and 20 in the control group. The frequencies of alleles A and G of SUMO4 were 67 and 33 in the patients with type 2 diabetes having retinopathy and 62 and 38 in the patients with type 2 diabetes without retinopathy. There genotypic and allelic frequencies of SUMO4 were not significantly (p>0.05) different between the patient and the control groups. Conclusions: The findings of the present study showed no correlation between M55V polymorphism of SUMO4 gene and diabetic retinopathy in type 2 diabetes patients of Iran. However, we emphasize that further studies is necessary to clarify the exact role of M55V polymorphism of SUMO4 in diabetic retinopathy in patients with type 2 diabetes