Frequency and Relevance of <scp> MYD88 ^L256P </scp> Mutation in Chronic Inflammatory Demyelinating Polyradiculoneuropathy and Multifocal Motor Neuropathy

Auteurs

Guérémy A, Boudjarane J, Alazard E, Fortanier E, Boucraut J, Abbou N, Grapperon AM, Kouton L, Verschueren A, Salort‐Campana E, Attarian S, Delmont E

Les auteurs en lien sont membres de l'INS.

Résumé

ABSTRACT Background The myeloid differentiation primary response 88 (MYD88) protein is involved in immune processes through the activation of the toll‐like receptors and the interleukin‐1 receptor. The acquired MYD88 L256P mutation enhances its activity and promotes inflammatory pathways and autoimmune diseases. Our aim was to determine the frequency of the MYD88 L256P mutation in chronic inflammatory demyelinating polyradiculoneuropathies (CIDP) and multifocal motor neuropathy with conduction blocks (MMN) and to assess its potential effect on the phenotype of the neuropathy. Methods The MYD88 L256P mutation was tested in the peripheral blood mononuclear cells of 79 CIDP, 35 MMN, and 57 controls with nonimmune mediated disorders. Disease severity was assessed on disability scores, neurofilament light chain dosages, motor unit counts, and sums of the sensory and motor amplitudes on electrodiagnostic tests. Results The MYD88 L256P mutation was more frequent in MMN patients (12/35, 34%; odds ratio 28 [95% confidence interval 4–1262]; p &lt; 0.001) and in CIDP patients (15/79, 19%; OR 13 [95% confidence interval 2–561]; p &lt; 0.001) than in controls (1/57, 2%). Patients with the MYD88

ABSTRACT Background The myeloid differentiation primary response 88 (MYD88) protein is involved in immune processes through the activation of the toll‐like receptors and the interleukin‐1 receptor. The acquired MYD88 L256P mutation enhances its activity and promotes inflammatory pathways and autoimmune diseases. Our aim was to determine the frequency of the MYD88 L256P mutation in chronic inflammatory demyelinating polyradiculoneuropathies (CIDP) and multifocal motor neuropathy with conduction blocks (MMN) and to assess its potential effect on the phenotype of the neuropathy. Methods The MYD88 L256P mutation was tested in the peripheral blood mononuclear cells of 79 CIDP, 35 MMN, and 57 controls with nonimmune mediated disorders. Disease severity was assessed on disability scores, neurofilament light chain dosages, motor unit counts, and sums of the sensory and motor amplitudes on electrodiagnostic tests. Results The MYD88 L256P mutation was more frequent in MMN patients (12/35, 34%; odds ratio 28 [95% confidence interval 4–1262]; p < 0.001) and in CIDP patients (15/79, 19%; OR 13 [95% confidence interval 2–561]; p < 0.001) than in controls (1/57, 2%). Patients with the MYD88

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