ACTN4 and heart disorder: ACTN2, a homolog of ACTN4, interacts with ACTN4 and missense mutations in ACTN2 are linked to a range of cardiac diseases.54 Annotation by ENCODE33 indicates that the 2 genome-wide significant variants (rs1808382 and rs3786835) associated with TortV near ACTN4 may have direct regulatory effects as they are located within a DNase I hypersensitivity site and in genomic regions enriched for promoter/enhancer histone marks in heart tissues (Table VI in the online-only Data Supplement).