<Dl> <Dt> LQT5 </Dt> </Dl> <P> LQT5 is an autosomal - recessive, relatively uncommon form of LQTS . It involves mutations in the gene KCNE1, which encodes for the potassium channel beta subunit MinK . In its rare homozygous forms, it can lead to Jervell and Lange - Nielsen syndrome . </P> <Dl> <Dt> LQT6 </Dt> </Dl> <P> LQT6 is an autosomal - dominant, relatively uncommon form of LQTS . It involves mutations in the gene KCNE2, which encodes for the potassium channel beta subunit MiRP1, constituting part of the I repolarizing K current . </P>

Qtc prolongation is most likely to occur in which of the following groups