Although only one mutation was found in the neck region, 11 were noted in the coiled-coil/tail region, among which half were located in the domain that interfaces with myosin light chain; in this regard it may be relevant that MYL2, which is required for cardiomyocyte differentiation in the murine heart (5), like MYH7, also exhibits increased expression in HLHS patients who carry MYH6 variants (Fig. 4 and Supplemental Table S3). The gene discussed is MYL2; the disease is hypoplastic left heart syndrome.