One individual was heterozygous for the MYBPC3 p.Gly531Arg pathogenic variant associated with hypertrophic cardiomyopathy (HCM), and two individuals were heterozygous for the KCNQ1 p.Arg397Trp (LP) variant implicated in long QT syndrome (LQTS). This evidence concerns the gene KCNQ1 and familial long QT syndrome.