Alterations of Complex II due to inherited homozygous mutations of its catalytic components (SDHA, SDHB, and SDHC) and of the SDHAF1 assembly factor are associated with a reduced number of neuromuscular pathologies (Table 1), including Leigh syndrome, cardiomyopathy, and infantile leukodystrophies. This evidence concerns the gene SDHA and cardiomyopathy.