Novel mutation in the membrane metalloendopeptidase gene in a patient with the autosomal recessive form of Charcot–Marie–Tooth disease

Abstract

Charcot-Marie-Tooth disease is a heterogeneous group of hereditary neuropathies. Diagnosis of the autosomal recessive form of Charcot-Marie-Tooth disease is challenging because of its genetic heterogeneity. Recently, mutations in the MME gene, which encodes neprilysin, have been shown to cause the autosomal recessive form of Charcot-Marie-Tooth disease 2T. Here, we present a female patient with the autosomal recessive form of Charcot-Marie-Tooth disease 2T carrying a novel mutation in MME (c.340_345delCTAGAA [p.(Leu113_Glu114del)]). She started to show numbness and weakness of her distal extremities from her 40 s. An electrophysiological study revealed sensorimotor neuropathy associated with preserved motor conduction velocity in the median nerve (45 m/s), whereas the compound muscle action potentials and sensory nerve action potentials of the lower limbs were markedly decreased. These findings further support the recent report that mutations in MME cause the autosomal recessive form of CharcotMarie-Tooth disease 2T.