Intermediate conduction velocity in two cases of Charcot-Marie-Tooth disease type 1A

• Published in: European journal of neurology 2024-05, Vol.31 (5), p.e16199
• Main Authors: Tomaselli, Pedro José, Blake, Julian, Polke, James M, do Nascimento, Osvaldo José Moreira, Reilly, Mary M, Marques Júnior, Wilson, Laurá, Matilde
• Format: Article
• Language: English
• Subjects: Age; Charcot-Marie-Tooth Disease - genetics; Conflicts of interest; Family; Genetic testing; Genotype & phenotype; Humans; Median Nerve; Nerve conduction; Neural Conduction; Neurology; Neuromuscular diseases; Neuropathy; Neurophysiology; Peripheral myelin protein 22; Phenotype; Phenotypes; Rare diseases; Stroke; Tooth diseases; Velocity
• ISSN: 1351-5101; 1468-1331; 1468-1331
• DOI: 10.1111/ene.16199

Charcot-Marie-Tooth disease type 1A (CMT1A) is the most prevalent hereditary neuropathy worldwide and classically has slow nerve conduction velocity (NCV), in most cases below 38 m/s. Two unrelated patients with motor NCVs in the upper limbs above 38 m/s are reported. Case report. Two genetically confirmed CMT1A patients are presented, from two unrelated families (one of British origin and the other of Brazilian origin). Both individuals had upper limb motor NCVs above 38 m/s, with values ranging from 41.9 to 45 m/s in the median nerve and from 42 to 42.3 m/s in the ulnar nerve. They presented with a very mild phenotype, with CMT Neuropathy Score version 2 (CMTNSv2) of 6 and 5, respectively. In contrast, affected family members within both kinships exhibited a classical phenotype with more severe disease manifestation (CMTNSv2 ranging from 12 to 20) and motor NCVs below 30 m/s. These cases, although very rare, highlight the importance of testing PMP22 duplication in patients with intermediate conduction velocities.