A Rare Case of Charcot-Marie-Tooth Disease Type 1C With an Unusual Presentation

Demyelinating Peripheral Neuropathy Caused by the p.R160H Mutation in the LITAF Gene

We report a 62-year-old woman who presented with complaints of numbness and tingling in her feet without a family history suggestive of neuropathy. Neurological examination and electromyogram testing confirmed the presence of a demyelinating neuropathy with a mild phenotype. Extensive testing revealed no etiology and she was diagnosed and treated unsuccessfully for chronic inflammatory demyelinating polyneuropathy. Ultimately, with the availability of next-generation sequencing, genetic testing revealed a heterozygous variant, chr16:11643500C > T, c.479 G > A, p.R160H, in the lipopolysaccharide-induced tumor necrosis factor (LITAF ) gene. Further analysis of this variant employing protein modeling suggests that this is a disease producing mutation causing Charcot Marie Tooth disease type 1C (CMT1C). Our study demonstrates the power of next-generation sequencing to diagnose patients with idiopathic neuropathy. This is important as it avoids unnecessary and expensive treatments for the patient and furthermore, allows genetic counseling for family members.

Atypical presentation of Charcot-Marie-Tooth disease type 1C with a new mutation: a case report

Background

Charcot-Marie-Tooth 1C (CMT1C) is a rare form of dominantly inherited CMT1 neuropathy caused by a mutated gene encoding lipopolysaccharide-induced tumour necrosis alpha factor (LITAF).

Case presentation

We report a 56-year-old patient with an atypical clinical phenotype of CMT1C, which started as progressive weakness of a single upper limb resembling acquired inflammatory neuropathy. Nerve conduction studies (NCS) and temporarily limited and partial effects of immunotherapy supported the diagnosis of inflammatory neuropathy. Significant progression of polyneuropathy, despite intensive long-lasting immunotherapy, together with repeatedly negative auxiliary investigations (CSF, MRI and antibodies) and genetic testing results finally led to the diagnosis of CMT1C neuropathy.

Conclusions

CMT1C should be added to the list of inherited neuropathies that need to be considered in suspected cases of inflammatory demyelinating neuropathy.