Figure 1
From: Genes and epigenetic processes as prospective pain targets
How polymorphisms can confer risk to pain. Single nucleotide polymorphisms (SNPs) can confer increased risk to pain by causing missense mutations that alter protein function. One of the most dramatic examples of this phenomenon is SNPs in the voltage-gated sodium channel Nav1.7. In this case, a SNP causing a change from an isoleucine to threonine residue in the loop domain leads to loss of channel inactivation, which is responsible for inherited paroxysmal pain disorder [27]. (a) Structure of Nav1.7. Arrow indicates the mutation in the loop domain. (b) Human embryonic kidney (HEK) cells transfected with wild-type Nav1.7 show normal channel inactivation. (c) HEK cells transfected with mutant Nav1.7 are unable to inactivate. Adapted with permission from [27].