Hyperactivity of the hypothalamic pituitary adrenocortical (HPA) axis is one of the main clinical findings in depression. The HPA axis is interrelated with glucocorticoid signaling via glucocorticoid receptors (GCRs). Thus, functional genetic variants on GCRs might influence therapeutic outcomes in depression. The aim of the present study was to investigate the association between three functional polymorphisms (rs41423247, rs6195, and rs6189/rs6190) on GCR and response to fluoxetine in a group of depressed patients. One hundred newly diagnosed patients completed 6 weeks of fluoxetine treatment. Response to treatment was defined as a 50% decrease in the Hamilton Depression Rating Scale score. Variants of rs41423247, rs6195, and rs6189/rs6190 polymorphisms were determined in extracted DNAs using PCR-RFLP method. Regarding rs41423247 polymorphism, carriers of the CG and GG genotype responded significantly better to fluoxetine compared with CC carriers (p=0.008, OR=3.3, 95% CI=1.35-8.07). Moreover, the G allele of rs41423247 polymorphism was strongly associated with response to fluoxetine (p=0.032, OR=2.2, 95% CI=1.09-4.44). There was no significant association between different genotypes and alleles of rs6195, rs6189/rs6190 variants, and response to fluoxetine (p=0.213 and 0.99, respectively). In conclusion, rs41423247 polymorphism might be a predictor for better response to fluoxetine. These findings support the idea that some variants of the GCR might contribute to interindividual variability of response to antidepressants.
Keywords: Depression; Fluoxetine; Genetic polymorphism; Glucocorticoids.