Met 158 variant of the COMT genotype is associated with thicker cortex in adult brain

Cortical thickness has been proposed as a new promising brain imaging endophenotype in elucidating the nature of gene-brain relationships. Here, we define the morphological impact of the Val158Met polymorphism in the catechol-O-methyltransferase (COMT) gene on human brain anatomy. One hundred and forty-nine adult healthy subjects (mean age: 40.716.1; ranging from 19 to 76 years) were genotyped (38 in the homozygous Val158 group; 80 in the Val158Met group; 31 in the homozygous Met158 group) for the COMT polymorphism and underwent morphological examination. Surface-based analysis of the cortical mantle showed that the COMT genotype was associated with structural differences in the right superior temporal sulcus and inferior prefrontal sulcus, where the individuals carrying the Met158 allele had a thicker cortex with respect to their Val158 counterparts. Our study extends the previous evidence found on pediatric population to the adult population, demonstrating that the higher synaptic dopamine levels associated with the presence of the Met158 allele may influence neuronal architecture in brain structures important for executive and emotional processing.