BLZF1 and cardiac conduction defect: Interestingly, these genes are contained within multi-gene loci previously associated with electrophysiological phenotypes and disorders: blzf1 is contained in a locus associated with cardiac repolarization (QT interval)32, rrad located in a locus associated with the specific human cardiac conduction disorder Brugada syndrome33, and a locus containing adprhl1 with left anterior fascicular block34.