Peroxynitrite can impair cardiac function via multiple mechanisms, including inhibition of cI and cIV by S‐nitrosation and nitrosylation, respectively (Burwell & Brookes, 2008; Chouchani et al, 2013; Pechanova et al, 2015), which in the case of GRAC mice could exacerbate the cardiomyopathy via a vicious circle‐type mechanism. Here, NDUFB6 is linked to cardiomyopathy.