Of the hundreds of individuals described with ACTA1-associated myopathy, only 12 (9 unique variants)57,58,59,60,61,62,63,64,65 have been reported to also have a cardiac abnormality (Table S1), either in conjunction with a skeletal myopathy (n = 10) or alone (n = 2). Here, ACTA1 is linked to skeletal muscle disorder.