A Patient With Charcot-Marie-Tooth Disease Type 4C (CMT4C) Presenting With Muscle Fasciculations and Motor Neuropathy

TL;DR

A 47-year-old patient with unusual symptoms was diagnosed with CMT4C, a rare genetic disorder, after genetic testing revealed two rare mutations.

Contribution

The study expands the known clinical and genetic features of Charcot-Marie-Tooth disease type 4C.

Findings

The patient showed motor neuropathy and later developed mild sensory symptoms over 10 years.

Genetic testing identified two rare variants in the SH3 domain and tetratricopeptide repeats 2 gene.

Protein modeling suggests these mutations are likely responsible for the patient's neuropathy.

Abstract

We report an unusual patient who, at age 47 years, had presented with complaints of muscle fasciculations. After neurological examination and electromyogram testing, he was diagnosed with motor neuropathy. Over the next 10 years, in addition to fasciculations, he developed numbness in his feet without any other symptoms. His current neurological examination at age 57 years was normal, except for mildly decreased light touch in the anterior portion of both feet. The nerve conduction studies performed repeatedly showed sensorimotor polyneuropathy with demyelination features. Blood tests, including anti-ganglioside antibodies, were normal. Genetic testing revealed two rare variants in trans in the SH3 domain and tetratricopeptide repeats 2gene, c.3413 G>A p.(S1138N) and c.3269 C>G p.(A1090G). Protein modeling suggests that these are disease-producing mutations and likely the cause of the neuropathy of our patient. Our study expands the clinical and genetic spectrum of patients with Charcot-Marie-Tooth disease type 4C.