Abstract Charcot-Marie-Tooth disease (CMT) is a group of clinically and genetically heterogeneous neuropathies classically divided into demyelinating (CMT1) and axonal forms (CMT2). The most common demyelinating form is CMT1A, due to a duplication in the gene encoding the peripheral myelin protein 22 (PMP22). Less frequently, mutations in the myelin protein zero gene (MPZ/P0) account for demyelinating CMT1B. Herein, we report a patient presenting with an isolated hyperCKemia in whom electrophysiological and pathological findings revealed a demyelinating and axonal neuropathy. Sequencing of the MPZ gene revealed a 306delA at codon 102 in the proband and in two relatives. This mutation has been already described in association with paucisymptomatic CMT without hyperCKemia.