Brown-Vialetto-Van Laere syndrome resulting from mutations in SLC52A2 can also be clearly distinguished from other neuropathies that may present with predominantly upper limb weakness, including distal hereditary motor neuropathies caused by mutations in BSCL2 or GARS, given that autosomal recessive mode of inheritance, the presence of a sensory neuropathy (in combination with a motor neuropathy), optic atrophy, hearing loss and respiratory insufficiency seen in our SLC52A2-specific cohort are not present in neuropathies caused by mutations in BSCL2 or GARS (Rossor et al., 2012). Here, SLC52A2 is linked to Leber hereditary optic neuropathy.