Genetics influence pain perception. For example, polymorphism rs4680 in the gene that encodes catechol-O-methyltransferase (COMT) results in the substitution of a methionine for the valine (wild type) at amino acid position 158, leading to a 3-4 fold reduction in COMT activity. Individuals homozygous for methionine at 158 have been shown to have greater pain perception […]