Charcot-Marie-Tooth disease type 2A (CMT2A) is caused by mutations in the mitofusin 2 (MFN2) genes associated with variable central nervous system (CNS) involvement. The authors report a case of a middle-aged woman with genetically confirmed CMT type 2 (CMT2), combined with delayed-onset bilateral optic neuropathy.

A 47-year-old woman presented with complaints of subacute decrease of visual acuity in both eyes. Her corrected visual acuity was 20/200 in the right eye and 20/320 in the left eye. Fundus photographs revealed bilateral disc pallor and diffuse retinal nerve fiber layer defects. No papillomacular bundle defect was observed. Goldmann perimetry showed central scotoma in both eyes. She had suffered from muscle wasting of the legs and foot deformities such as high arches and hammer toes since childhood and required a wheelchair for ambulation. A series of CMT gene mutation tests revealed an MFN2 gene mutation, c.617C>T (p.Thr206Ile), and the patient was diagnosed with CMT2A.

Charcot-Marie-Tooth disease is a common inherited neuromuscular disorder and CMT2A, an axonal CMT neuropathy, is associated with bilateral optic neuropathy. Therefore, suspecting CMT and testing for gene mutations as part of the work-up in patients with subacute bilateral optic neuropathy associated with peripheral neuropathy is critical.