Affiliations: [a] Service de Biochimie et Biologie moléculaire Grand Est, Unité Médicale Pathologies neurologiques et cardiologiques, Centre de Biologie et de Pathologie Est, Hospices Civils de Lyon, Bron, France
| [b] Referral Centre for ALS and Neuromuscular Diseases, Hospital La Timone 264 rue Saint Pierre, 13005, Marseille, France
| [c]
Aix Marseille University, INSERM, GMGF, Marseille, France
| [d] Medical Genetics Department, La Timone Teaching hospital, 264, rue Saint-Pierre, 13385 Marseille, France
Correspondence:
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Correspondence to: Thibaut Benquey, Service de Biochimie –Biologie Moléculaire, Centre de Biologie Est –Centre Hospitalier Grand Est, 59 Boulevard Pinel, 69500 Bron. Tel.: +33 04 72 35 69 88; E-mail: thibaut.benquey@chu-lyon.fr.
Abstract: Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant inherited disorder commonly presenting with acute-onset, non-painful focal sensory and motor mono neuropathy. In 80% of cases, the genetic defect is a 1.5 Mb deletion on chromosome 17p11.2, including PMP22. Only few cases of partial deletion and point mutations in PMP22 are involved in HNPP. We investigated a 62-years-old man with lower limb plexopathy first considered as Garland’s syndrome. A month later, his 29 years old son also consulted for paresthesia on the peroneal nerve. Targeted sequencing of the PMP22 gene identified a c.370delT (p.Trp124Glyfs*31) in both affected patients. We report a new PMP22 point mutation associated with an atypical clinical phenotype of HNPP, a painful plexopathy of the lower limb worsenen by diabetes and a mere paresthesia, but a typical ENMG. This study illustrates the large spectrum of the disease, and emphasizes the importance of a complete ENMG and family history.
Keywords: HNPP, PMP22 gene, point mutations, phenotypic heterogeneity
