SCN8A and trigeminal nerve disorder: Expression of NaV1.6 is significantly increased in human skin biopsies taken from patients with complex regional pain syndrome and post‐herpetic neuralgia, and most interestingly, a recent study reported a gain‐of‐function mutation of this subunit in a patient with trigeminal neuralgia, adding to evidence from animal studies to support a role for this channel in pain (Dib‐Hajj et al., 1996; Sittl et al., 2012; Tanaka et al., 2016; Xie et al., 2013, 2015; Zhao et al., 2008).