AARS2 and hypertrophic cardiomyopathy: 2011). The renal disease of patient I was not fully investigated, so we cannot judge whether the disease is of the same kind as in SARS2 deficiency or not. Patient II, who was compound heterozygous for mutations in PARS2, developed dilated and hypertrophic cardiomyopathy at 2 years of age. Mutations in AARS2, the gene encoding the mitochondrial alanyl-tRNA synthetase, have also been associated with infantile mitochondrial cardiomyopathy (Gotz et al. 2011).