KCNQ1 and long QT syndrome 1: In addition to a homozygous frameshift mutation in USH2A, c.236_239dup p.(Gln81Tyrfs*28), proband 58 presented with a medically actionable pathogenic variant, c.733_734del p.(Gly245Argfs*39) in KCNQ1 (Table 1) (Amirian et al. 2018), which is associated with long QT syndrome 1 (OMIM 192500) and familial atrial fibrillation 3 (OMIM 607554).