A New Point Mutation in the PMP22 Gene in a Family Suffering From Atypical HNPP

J Neuromuscul Dis. 2020;7(4):505-510. doi: 10.3233/JND-190460.


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; phenotypic heterogeneity; point mutations.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Arthrogryposis / diagnosis
  • Arthrogryposis / genetics*
  • Arthrogryposis / physiopathology*
  • Hereditary Sensory and Motor Neuropathy / diagnosis
  • Hereditary Sensory and Motor Neuropathy / genetics*
  • Hereditary Sensory and Motor Neuropathy / physiopathology*
  • Humans
  • Male
  • Middle Aged
  • Myelin Proteins / genetics*
  • Pedigree
  • Phenotype
  • Point Mutation


  • Myelin Proteins
  • PMP22 protein, human

Supplementary concepts

  • Tomaculous neuropathy