Charcot-Marie-Tooth Disease Type 2A
- 1 August 2014
- journal article
- review article
- Published by American Medical Association (AMA) in JAMA Neurology
- Vol. 71 (8), 1036-1042
- https://doi.org/10.1001/jamaneurol.2014.629
Abstract
Importance Axonal Charcot-Marie-Tooth disease (CMT) is genetically heterogeneous, with 11 genes identified. Axonal CMT has most frequently been associated with mutations in theMFN2gene (CMT2A). Objectives To describe the clinical and molecular features of CMT2A, to delineate prognostic factors, to understand connections between a certain phenotype and more serious clinical consequences, and to identify interactions among the associated genes. Evidence Review We describe the clinical, molecular, electrophysiological, and additional features of 43 patients with CMT2A. The degree of physical disability was determined by the CMT neuropathy score and adapted to the CMT neuropathy score gradient to evaluate the clinical course. We evaluated all data within the context of the most recent and important publications concerning this issue. Findings Twenty-five patients had early-onset CMT2A and severe functional disability, with 9 being wheelchair bound, and 18 had late-onset disease and a milder phenotype. Optic atrophy, vocal cord palsy, and auditory impairment were observed in 5, 6, and 2 patients, respectively. Among the 24 patients who underwent magnetic resonance imaging of the spinal cord, 6 had evidence of spinal atrophy with or without hydromyelia. In 1 patient, magnetic resonance imaging revealed hydrocephalus. Twenty differentMFN2mutations were identified, and 14 were considered new variants. Their transmission was predominantly autosomal dominant, with vertical transmission in 8 and de novo occurrence in 3. However, we also identified rare types of transmission, especially a germinal mosaicism and an autosomal recessive inheritance. One patient carried a rare variant in theGDAP1gene and another in theOPA1gene in association withMFN2mutation. Conclusions and Relevance Charcot-Marie-Tooth disease type 2A associated withMFN2mutations is clinically very heterogeneous. Ranging from a mild to a severe form, CMT2A exhibits various types of transmission. Optic atrophy and vocal cord palsy were observed in patients with severe disability and an early-onset form and also in patients with later onset. Hydromyelia and spinal cord atrophy support central nervous system involvement in CMT2A.Keywords
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