Charcot–Marie–Tooth disease
HNPP is caused by a mutation in the gene "PMP22", which makes peripheral myelin protein 22. This protein has a role in the maintenance of the myelin sheath that insulates nerves, resulting in insufficient conductivity in the nerves. HNPP is part of the group of hereditary motor and sensory neuropathy (HMSN) disorders and is linked to Charcot–Marie–Tooth disease (CMT).