Genetic contribution of catechol‐O‐methyltransferase in hippocampal structural and functional changes of female migraine sufferers

Physiological and emotional stressors are associated with or provoke each migraine attack and cause structural and functional changes in the central nervous system. The hippocampus, a limbic structure important in anxiety‐related behavior, is vulnerable to long‐term stress. Given that catechol‐O‐methyltransferase (COMT) is widely distributed in the hippocampus and its genetic variation is thought to contribute to the interindividual variability in pain perception and anxiety regulation, whether or not migraine and COMT val¹⁵⁸met genotype have an interactive effect in the key brain area related to maladaptive stress, the hippocampus, is still poorly understood. Using T1‐weighted and resting functional MRI, we evaluated the effect of COMT genetic variations on migraine and possible interactions between COMT and the disease in brain structure and function in 135 females with migraine without aura (MWoA) and 111 matched health controls (HC). Optimized voxel‐based morphometry (VBM) and functional connectivity (FC) analyses were applied. From the whole brain VBM analysis, we found a significant disease × genotype interaction in the hippocampus, which overlapped with disease‐related increase of gray matter (GM) in val homozygote migraineurs. In our results, increased GM in the hippocampus was only found in val homozygote MWoA compared to val homozygote HC. Moreover, FC between the hippocampus and the medial prefrontal cortex was significantly decreased in val homozygotes, and it was negatively correlated with self‐rating anxiety scale values.Our results indicated that brain structure and function of the hippocampus are differentially affected by migraine in val homozygotes compared with met carriers. Hum Brain Mapp 36:1782–1795, 2015. © 2015 Wiley Periodicals, Inc .