I am heterozygote carrier of rs1805124, which is sometimes associated to cardiac arrythmia and some other cardiac deffects (which I don't have yet to my knowledge). This sodium channel mutation is not known to be associated with any other pathology, but another mutation in this gene is already linked to IBS, and Nav1.5 are not only in cardiac myocytes, they seems to be also present in the brain. This mutation produces a gain of function of the channel. Ion channels functions are indirectely involved in our syndrome, and polymorphisms of these channels are likely to have some impact in our clinical outcome, so more investigations on it is warranted. Note: One of the mutations found in hypokalemia periodic paralysis, a genetic channelopathy, is on the SCN4A gene (Nav1.4).