Met158 variant of the catechol-O-methyltransferase 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 Val(158)Met polymorphism in the catechol-O-methyltransferase (COMT) gene on human brain anatomy. One hundred and forty-nine adult healthy subjects (mean age: 40.7+/-16.1; ranging from 19 to 76 years) were genotyped (38 in the homozygous Val(158) group; 80 in the Val(158)Met group; 31 in the homozygous Met(158) 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 Met(158) allele had a thicker cortex with respect to their Val(158) 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 Met(158) allele may influence neuronal architecture in brain structures important for executive and emotional processing.