MSTO1-related mitochondrial myopathy and ataxia (MIM#617675) is caused by monoallelic pathogenic variants in MSTO1 (MIM*617619) leading to an autosomal dominant disease or biallelic variants in MSTO1 leading to a recessive disease. This evidence concerns the gene MSTO1 and mitochondrial myopathy-cerebellar ataxia-pigmentary retinopathy syndrome.