Genetic variants in inflammatory cytokines and angiogenesis associated with diabetic nephropathy- A meta-analysis

Background Diabetes mellitus (DM) is the most common chronic endocrine disorder, affecting an estimated 371 million people worldwide. It is associated with microvascular and macrovascular complications, including diabetic nephropathy (DN), a primary cause of end-stage renal disease (ESRD). Among the Gulf countries, Saudi Arabia has the highest number of people with diabetes and about 30-40% diabetic patients suffer from DN. Diabetes imposes a large economic burden on healthcare systems. Healthcare expenditures due to diabetes account for 11% of the total medical expenditures in the world in 2011. Mostly, individuals exposed to long durations of diabetes with relatively poor glycemic control develop progressive DN. However, some patients appear to be at increased risk while some will remain relatively protected. Differential disease risk in DN may be partly attributable to genetic susceptibility. A recent review identified genetic variants in the ACE and MTHFR genes to be significantly associated with type 2 diabetes in Arabs [1]. Inflammatory cytokines and angiogenic factors are important modulators in the pathogenesis of DN. We aimed to determine which of the previously investigated genetic variants in these pathways are significantly associated with the development of DN in diabetes and to examine the functional role of these genes.