Since 2003, phenotype-genotype studies have led to the identification of syndromic DOA phenotypes, the so-called DOA “plus” (DOA+; MIM# 125250) syndromes, mainly occurring in young adults and associating OPA1 variants with optic atrophy and sensorineural deafness [15, 16], ataxia, myopathy, peripheral neuropathy, and progressive external ophthalmoplegia [17–22] in up to 20% of the patients [23]. This evidence concerns the gene OPA1 and peripheral neuropathy.