SCN9A and irritable bowel syndrome: The voltage-gated sodium (Nav) [46,83], calcium (Cav), specifically Cav3.2 [8], transient receptor potential vanilloid TRPV1, TRPV3, TRPV4, and TRPA1 [45,77], voltage-gated sodium (Nav) (Nav1.1, Nav1.3, Nav1.5, Nav1.6, Nav1.7, Nav1.8, and Nav1.9) [5,94], and big/large-conductance Ca2+-activated K (BKCa) channels [23,95] are involved in the genesis of visceral hypersensitivity in IBS.