TRDN and familial long QT syndrome: Another four genes associated with atypical LQTS, where prolongation is connected with neonatal heart block of autosomal-recessive inheritance had definitive or strong evidence (definitive: CALM1 (calmodulin 1), CALM2 (calmodulin 2), CALM3 (calmodulin 3); strong: TRDN (triadin))[21].