Novel mutations in NEB cause abnormal nebulin expression and markedly impaired muscle force generation in severe nemaline myopathy

Michael W. Lawlor, Coen A. Ottenheijm, Vilma Lotta Lehtokari, Kiyomi Cho, Katarina Pelin, Carina Wallgren-Pettersson, Henk Granzier, Alan H. Beggs

Research output: Contribution to journalArticlepeer-review

52 Scopus citations

Abstract

Background: Nemaline myopathy (NM) is a congenital muscle disease associated with weakness and the presence of nemaline bodies (rods) in muscle fibers. Mutations in seven genes have been associated with NM, but the most commonly mutated gene is nebulin (NEB), which is thought to account for roughly 50% of cases.Results: We describe two siblings with severe NM, arthrogryposis and neonatal death caused by two novel NEB mutations: a point mutation in intron 13 and a frameshift mutation in exon 81. Levels of detectable nebulin protein were significantly lower than those in normal control muscle biopsies or those from patients with less severe NM due to deletion of NEB exon 55. Mechanical studies of skinned myofibers revealed marked impairment of force development, with an increase in tension cost.Conclusions: Our findings demonstrate that the mechanical phenotype of severe NM is the consequence of mutations that severely reduce nebulin protein levels and suggest that the level of nebulin expression may correlate with the severity of disease.

Original languageEnglish (US)
Article number23
JournalSkeletal muscle
Volume1
Issue number1
DOIs
StatePublished - Jun 20 2011

Keywords

  • Congenital myopathy
  • Nebulin
  • Nemaline myopathy
  • Nemaline rod (body)
  • Thin filament

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Molecular Biology
  • Cell Biology

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