Polymorphisms of Genes for Brain-Derived Neurotrophic Factor, Methylenetetrahydrofolate Reductase, Tyrosine Hydroxylase, and Endothelial Nitric Oxide Synthase in Depression and Metabolic Syndrome

The prevalence of metabolic syndrome as well as the occurrence of depressive disorder, which are both connected with increased risk of diabetes mellitus type 2 and cardiovascular diseases, is continually increasing worldwide. These disorders are interconnected at various levels; the genetic one seems to be promising. Contribution of genetic factors to the aetiopathogenesis of depressive disorder weighs within the range 40-50 %, whereas the genetic background for the manifestation of metabolic syndrome is more complicated. In this pilot study, we investigated the incidence of polymorphisms in several genes supposed to play a role in the development of both depressive disorder and metabolic syndrome such as brain-derived neurotrophic factor, methylenetetrahydrofolate reductase, tyrosine hydroxylase, and endothelial nitric oxide synthase. The entire group consisted of 42 patients with depressive disorder, 57 probands with metabolic syndrome and 41 control individuals. We found that genotype Met/Met of the Val66Met polymorphism of the brain-derived neurotrophic factor gene was positively associated with depressive disorder (P < 0.05), but we were not able to find any significant associations of both the depressive disorder and metabolic syndrome with the remaining polymorphisms studied (methylenetetrahydrofolate reductase 677CT, methylenetetrahydrofolate reductase 1298AC, endothelial nitric oxide synthase Glu298Asp, and tyrosine hydroxylase).