G-protein β3 subunit genetic variation moderates five-year depressive symptom trajectories of primary care attendees

Response to sertraline is influenced by GNβ3 gene G-350A variant in patients with major depressive disorder

PURPOSE

Heterotrimeric guanine nucleotide-binding proteins (G proteins) are a major group of human genome membrane protein receptors. Genetic variation in the β3 subunit (GNβ3) associated with gene splicing and increased activity is associated with major depressive disorder (MDD). However, the effect of G-350A GNβ3 genetic polymorphism and therapeutic outcome of selective serotonin reuptake inhibitors (SSRIs) in MDD has not yet been studied.

METHOD

One hundred newly diagnosed MDD patients were treated with sertraline for 6 weeks. The severity of depressive symptoms was weekly assessed by Hamilton Rating Scale for Depression (HRSD). A 50% decrease in HRSD was defined as response to treatment. GNβ3 polymorphisms (G-350A, A657T) were determined in each individual using a PCR-RFLP technique.

RESULTS

Our results suggested that subjects with GG genotype of G-350A responded 5.9-folds more to sertraline compared to carriers of other variants (P = 0.004, OR = 5.9; 95% CI = 1.66-21.99). In addition, carriers of the G allele responded 1.9-folds more to sertraline than carriers of the A allele (P = 0.032, OR = 1.92; 95% CI = 1.05-3.65). However, no association was observed between A657T variants and response to sertraline (P = 0.920, OR = 0.9; 95% CI = 0.31-2.69).

CONCLUSION

The results suggest that G-350A variant of GNβ3 plays a foremost part as a predictor of response to antidepressant treatment.

A Functional Polymorphism in the DRD1 Gene, That Modulates Its Regulation by miR-504, Is Associated with Depressive Symptoms

OBJECTIVE

The aim of this study was to examine a possible association between depressive symptoms and a functional polymorphism (rs686) that modulates the regulation of DRD1 gene by miR-504.

METHODS

A total of 239 young Colombian subjects were evaluated with the Patient Health Questionnaire-9 (PHQ-9) scale and genotyped for the rs686 polymorphism. A linear regression model, corrected by age and gender, was used.

RESULTS

A significant association between the rs686 polymorphism and PHQ-9 scores was found, under a dominant genetic model (p=0.0094).

CONCLUSION

These results provide novel evidence about the growing role of inherited variants in binding sites for brain-expressed miRNAs on depressive symptomatology.