Novel EXOSC9 variants cause pontocerebellar hypoplasia type 1D with spinal motor neuronopathy and cerebellar atrophy

J Hum Genet. 2021 Apr;66(4):401-407. doi: 10.1038/s10038-020-00853-2. Epub 2020 Oct 10.

Abstract

Pontocerebellar hypoplasia (PCH) is currently classified into 13 subgroups and many gene variants associated with PCH have been identified by next generation sequencing. PCH type 1 is a rare heterogeneous neurodegenerative disorder. The clinical presentation includes early-onset severe developmental delay, progressive motor neuronopathy, and cerebellar and pontine atrophy. Recently two variants in the EXOSC9 gene (MIM: 606180), NM_001034194.1: c.41T>C (p.Leu14Pro) and c.481C>T (p.Arg161*) were identified in four unrelated patients with PCH type 1D (PCH1D) (MIM: 618065). EXOSC9 encodes a component of the exosome complex, which is essential for correct processing and degradation of RNA. We report here two PCH1D families with biallelic EXOSC9 variants: c.239T>G (p.Leu80Arg) and c.484dupA (p.Arg162Lysfs*3) in one family and c.151G>C (p.Gly51Arg) in the other family. Although the patients studied here showed similar clinical features as previously described for PCH1D, relatively greater intellectual development (although still highly restricted) and normal pontine structure were recognized. Our findings expand the clinical consequences of biallelic EXOSC9 variants.

Publication types

  • Case Reports

MeSH terms

  • Atrophy / complications
  • Atrophy / genetics
  • Atrophy / pathology*
  • Cerebellar Diseases / complications
  • Cerebellar Diseases / genetics
  • Cerebellar Diseases / pathology*
  • Exosome Multienzyme Ribonuclease Complex / genetics*
  • Female
  • Genetic Association Studies
  • Humans
  • Infant
  • Male
  • Motor Neuron Disease / complications
  • Motor Neuron Disease / genetics
  • Motor Neuron Disease / pathology*
  • Muscular Atrophy, Spinal / complications
  • Muscular Atrophy, Spinal / genetics
  • Muscular Atrophy, Spinal / pathology*
  • Mutation*
  • Olivopontocerebellar Atrophies / complications
  • Olivopontocerebellar Atrophies / genetics
  • Olivopontocerebellar Atrophies / pathology*
  • Pedigree
  • RNA-Binding Proteins / genetics*

Substances

  • EXOSC9 protein, human
  • RNA-Binding Proteins
  • Exosome Multienzyme Ribonuclease Complex

Supplementary concepts

  • Pontocerebellar Hypoplasia Type 1