Although Pt827 was enrolled with a diagnosis of mitochondrial disease, after comprehensive genomic analyses, the clinical diagnosis was changed to cardiomyopathy, familial restrictive (OMIM: 115210) caused by a mutation in TNNI3. Jia et al reported a link between Tnni3 and mitochondrial dysfunction using knockout mice [35]. Here, TNNI3 is linked to cardiomyopathy.