Clinical and pathological features in Charcot-Marie-Tooth disease type 2A2: a family report

Abstract

Objective To report clinical and pathological features in a Chinese family with CharcotMarie-Tooth disease type 2A2 (CMT2A2). Methods There were 5 patients (2 male and 3 female) in a family with an autosomal dominant inheritance pattern. The index case was a 36 years old woman. She developed progressive distal limb weakness at the age of 6, with pescavus at the age of 8. Other 4 family members presented with similar symptoms between the age of 3-7. Physical examination showed distal limb weakness and wasting, loss of sensory and contracture in all of them. Nerve conduction velocity revealed non-potential in several motor and sensory nerves in the proband and her son. Sural nerve biopsy was performed on the proband. The sequence of MFN2 gene was analyzed in DNA from 5 patients and 3 asymptomatic members. Results Sural nerve biopsy revealed severe loss of myelinated fibers with few regenerating clusters. Electron microscopy revealed aggregation of mitochondrian in the axons. A R94W mutation in MFN2 gene has been identified in 5 patients, but not in unaffected members. Conclusions We confirmed Chinese CMT2A2. Absent of regenerating cluster in the nerve indicated that MFN2 mutation predominantly resulted in lesions in the neurons. Key words: Charcot-Marie-Tooth disease; Membrane proteins; Mitochondrial proteins; Mutation