Risk of depression in subjects with type 2 diabetes Is modulated by a genetic variant within DRD4 gene: North Indian diabetes-depression link exploration study (NIDDLES)

The role and relevance of DRD4 gene SNPs for the risk of depression in type 2 diabetes remains to be clarified. To investigate its association, present cross sectional study was conducted on 399 type 2 diabetics who were diagnosed for depression using primary health care questionnaire-9 (PHQ-9) > 10 criteria. 191 subjects were depressed whereas, 208 subjects were found to be clinically non-depressed. Minor allele frequencies of two DRD4 SNPs rs1800955 and rs747302 were 0.45, 0.42 and 0.42, 0.34 in depressed and non depressed subjects respectively. C allele of rs747302 showed risk of depression (OR 1.41 95% CI 1.05- 1.87, P= 0.024) in comparison to G allele. It has been observed that carriers of CC genotype had approximately double the risk of depression (OR 1.96 95% CI 1.08- 3.56, P= 0.03) than GG carriers and this risk manifests in recessive mode.