Sexually divergent effect of COMT Val/met genotype on subcortical volumes in schizophrenia

Structural and functional alterations of subcortical areas have been observed in schizophrenia. COMT Val108/158Met has been associated with schizophrenia and implicated in different cognitive and neurofunctional alterations. Recent studies suggested that COMT genotype influences neuronal growth. Genetic variations in COMT were associated with sexually dimorphic effects on enzymatic activity, brain anatomy and behavior suggesting that gender might be crucial in interpreting COMT-dependent effects. Based on these data, we investigated possible effects of the interaction between COMT Val108/158Met genotype and gender on subcortical volumes among 79 patients with schizophrenia. All patients were genotyped for COMT Val108/158Met polymorphism and underwent 3 T-MRI. Volumetric segmentation of subcortical structures was performed with Freesurfer 5.3. The general linear model yielded no significant effect of COMT genotype alone, thus revealing a significant interaction of gender and COMT gene on subcortical volumes. The overall significance of the interaction was driven by significant effects in the right caudate, and bilaterally in putamen, pallidum, and nucleus accumbens. Post-hoc analyses showed that female Met/Met patients had smaller volumes, whereas male subjects homozygous for the Met allele showed higher or not different subcortical volumes compared to the other groups. This study reports a sexually divergent effect of COMT polymorphism on subcortical structures in schizophrenia. These results support the hypothesis of a sexually dimorphic effect of COMT genetic variations on brain morphology.