MYH6 and hypoplastic left heart syndrome: Reduced ejection fraction, a measure of systolic ventricular function, was also noted in 2 subjects with HLHS who had recessive MYH6 mutations.102 A case‐control study of 190 patients with HLHS noted an increased burden of damaging MYH6 variants in HLHS cases versus 1000 Genomes Project controls and reduced transplant‐free survival in HLHS patients with MYH6 mutations compared with other HLHS patients.103 The differential survival was potentially due to impaired cardiomyogenesis and to dysregulation of genes related to myocardial structure and function.