This voxelwise analysis study reported a combined effect of five genetic SNPs, that is, COMT Val158Met, clusterin CLU, neuregulin 1 receptor (ErbB4), neurotrophic tyrosine kinase receptor‐type 1 (NTRK1), and the hemochromatosis gene (HFE) which explained ∼6% of the variance in the average FA of the corpus callosum including the genu, body, and splenium in young, healthy individuals. This evidence concerns the gene NTRK1 and hemochromatosis.