The emphasis that we have placed on cell adhesion molecule genes here should not obscure the identification of a large number of genes that encode proteins that are more classically “druggable”. Enzymes, receptors and ligands (G-protein coupled receptors, ligand-gated ion channels and peptide ligands), ion channels and transporters, in particular, provide targets for many currently-effective drugs and are thus thought of as more “druggable” than cell adhesion molecules, for which there is less precedent for efficacious small molecule therapeutics. It is therefore instructive to identify the potential targets that come from genes in these families that are supported from results in replicated genome wide association studies of at least three of the phenotypes assessed in this review. It is worth noting that many of these drug targets in fact can be targeted by promising lead compounds that have already been identified (see below).
