Cardiomyopathy, or a deterioration of the ability of the heart muscle to contract, generally leads to progressive heart failure. It is frequently inherited, and, because approximately 40% of affected children are likely to die within five years of diagnosis, being able to identify its genetic basis is particularly important. Now, we have identified a new disease gene, superoxide dismutase 2 (SOD2) which is implicated in the development of severe paediatric cardiomyopathy. SOD2 is an enzyme that scavenges oxygen radicals that are produced during normal energy metabolism of the cells. The SOD2 variant was shown to affect the catalytic activity of the protein, leading to excess oxygen radical levels that can have strongly damaging effects in the neonatal heart. Our findings offer new clues for future studies into the pathogenesis of cardiomyopathy and may contribute to the development of gene-tailored management strategies. (By Dr. Johanna Herkert, https://jmg.bmj.com/content/early/2019/09/06/jmedgenet-2019-106330 )