For example, incomplete phenotyping could misguide the provider into ordering a targeted LQTS panel after exertional syncope, when the proband actually has CPVT and harbors a pathogenic variant in the cardiac ryanodine receptor (RyR2).12 Therefore, thorough phenotyping and detailed three-generation family history-taking are essential to informing the provider’s choice for the correct genetic test to order so as to avoid false negatives. Here, RYR2 is linked to catecholaminergic polymorphic ventricular tachycardia.