Specific mutant gene is responsible for function of K channels and it is located on short branch (part) of the 11-th pair of chromosome 11p15.5 (KVLQT-LQT1), long branch of the 7-th pair of chromosomes 7q35-36 (K- HERG-LQT2), as well as on the 21-st pair of chromosome (KCNE1-LQT5). 