Genetically confirmed Charcot-Marie-Tooth disease type 2A manifesting with postural tremor: a case report.

Abstract

Background: Charcot-Marie-Tooth disease is a spectrum of inherited disorders characterized by both motor and sensory manifestations, which include prominent distal muscle weakness, foot deformities (pes cavus and hammer toes), and sensory deficits. Postural tremor as a manifestation of Charcot-Marie-Tooth is seldom present, except in a variant of Charcot-Marie-Tooth subtype 1 (Roussy-Levy syndrome), and its presence often results in a diagnostic dilemma.

Case presentation: We present a 34-year-old Eritrean man who came to our hospital with a complaint of tremors of the hands of 6 months duration. Associated with this, he had difficulty walking and weakness of the distal extremities bilaterally, prominently involving the lower limbs. The patient denied a family history of such illness. Physical examination revealed distal muscle weakness (4+/5 on upper limbs, while 3/5 on lower limbs bilaterally), pes cavus deformity, absent ankle reflexes, and mild vibratory sensory loss. We noted a postural tremor that attenuated when the patient assumed an anatomic position. The tremor was limited to the hands. Nerve conduction study of upper and lower limbs showed moderate to severe motor axonal and demyelinating polyneuropathy (axonal > demyelinating), suggestive of mixed axonal and demyelinating hereditary polyneuropathy. Subsequently, genetic testing revealed copy number changes (heterozygous deletion) on the MPZ and MFN2, while the PMP22 gene showed ambiguous copy number changes (decrease) on exons 2 and 3. Tying the clinical, electrophysiologic, and genetic findings, consideration of Charcot-Marie-Tooth subtype 2A with postural tremor was made. Subsequently, the patient was managed with regular physiotherapy and an anxiolytic resulting in minimal symptom improvement.

Conclusion: The present case describes a 34-year-old male patient with Charcot-Marie-Tooth subtype 2A presenting with neuropathic postural tremor, which is a rare presentation of a common hereditary polyneuropathy. This case highlights the fact that tremors can be associated with peripheral neuropathy syndromes, and a high index of suspicion is needed to rightly diagnose our patients.