Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) diagnosis is mainly based on the clinical examination and the electromyogram. CIDP is sometimes confused with another demyelinating neuropathy, type 1 Charcot-Marie-Tooth disease. In an article from June 2021, French, Belgian and Swiss neurologists thus identified 35 CMT patients in a cohort of 1,104 CIDP patients, or 3.2%.
Their genetic analysis showed abnormalities in the PMP22 genes (34% of CMT patients), MPZ (31%) and 10 other genes known to be responsible for CMT.
By comparing the 35 patients with CMT to 35 other patients in the cohort, with CIDP:
- CMT starts earlier (39 years on average versus 56 years for IPDC),
- motor weakness is present in 80% of patients with CMT at the time of diagnosis (compared to 29% of patients with CIDP)
- MRI imaging of the brachial plexus is normal in 70% of patients with CMT (versus 40% of patients with CIDP)
- patients with CMT respond less well to treatment with immunosuppressants.
The authors recommend performing genetic analyzes for CMT in anyone suspected of having CIDP, a strategy that is less expensive than mistakenly treating patients with CMT with immunosuppressive therapies (4.6M € vs 2.7M €).
On the same topic: Although rare, border forms between CIDP and CMT also exist in children.
Charcot-Marie-Tooth disease misdiagnosed as chronic inflammatory demyelinating polyradiculoneuropathy: an international multicentric retrospective study. Hauw F, Fargeot G, Adams D, Attarian S, Cauquil C, Chanson JB, Créange A, Gendre T, Deiva K, Delmont E, Francou B, Genestet S, Kuntzer T, Latour P, Le Masson G, Magy L, Nardin C, Ochsner F, Sole G, Stojkovic T, Maisonobe T, Tard C, Van den Berghe P, Echaniz-Laguna A. Eur J Neurol. 2021 (Juin).