A novel MPZ mutation in Charcot-Marie-Tooth disease type 1B with focally folded myelin and multiple entrapment neuropathies.

Charcot-Marie-Tooth type 1B (CMT1B) is a demyelinating neuropathy caused by mutations in the myelin protein zero (MPZ) gene. Here, we describe a patient with CMT1B with focally folded myelin, a rarely reported phenotype of CMT1B, who initially presented with multiple entrapment neuropathies. She complained of palmar dysesthesia on both sides and on both soles of her feet in her 30's. She underwent bilateral carpal and tarsal tunnel release at age 44, which provided transient relief from the symptoms. A sural nerve biopsy performed at age 49 revealed focally folded myelin. Molecular genetic analysis revealed a novel Asn131Ser mutation in MPZ.