PRPS1 and Charcot-Marie-Tooth disease X-linked recessive 5: A further hemizygous mutation c.82G > C (p.G28R) has been reported in a Japanese male with CMTX5 with typical clinical features, i.e., neuropathy, optic atrophy, and hearing loss, but with only mild loss of PRPS1 activity in erythrocytes [180].