title: A Premature Stop Codon in MYO18B is Associated with Severe Nemaline Myopathy with Cardiomyopathy.
abstract: BACKGROUND
  Nemaline myopathies (NM) are rare and severe muscle diseases characterized by the presence of nemaline bodies (rods) in muscle fibers. Although ten genes have been implicated in the etiology of NM, an important number of patients remain without a molecular diagnosis.
  
  
  OBJECTIVE
  Here we describe the clinical and histopathological features of a sporadic case presenting with severe NM and cardiomyopathy. Using exome sequencing, we aimed to identify the causative gene.
  
  
  RESULTS
  We identified a homozygous nonsense mutation in the last exon of MYO18B, leading to a truncated protein lacking the most C-terminal part. MYO18B codes for an unconventional myosin protein and it is mainly expressed in skeletal and cardiac muscles, two tissues severely affected in the patient. We showed that the mutation does not impact on mRNA stability. Immunostaining and Western blot confirmed the absence of the full-length protein.
  
  
  CONCLUSIONS
  We propose MYO18B as a novel gene associated with nemaline myopathy and cardiomyopathy.
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, GH Pitié-Salpêtrière, 47 Boulevard de l'hôpital, 75013 Paris, France.|Unité de Morphologie Neuromusculaire, Institut de Myologie, Groupe Hospitalier Universitaire La Pitié-Salpêtrière; Paris, France.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Malfatti
authors.affiliation: Department of Translational Medecine, IGBMC, Illkirch, France.|INSERM U964, Illkirch, France.|CNRS, UMR7104, Illkirch, France.|Strasbourg University, Illkirch, France.
authors.forename: Johann
authors.initials: J
authors.lastname: Böhm
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, GH Pitié-Salpêtrière, 47 Boulevard de l'hôpital, 75013 Paris, France.|Unité de Morphologie Neuromusculaire, Institut de Myologie, Groupe Hospitalier Universitaire La Pitié-Salpêtrière; Paris, France.|Centre de référence de Pathologie Neuromusculaire Paris-Est, Institut de Myologie, GHU La Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris; Paris, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Lacène
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, GH Pitié-Salpêtrière, 47 Boulevard de l'hôpital, 75013 Paris, France.|Unité de Morphologie Neuromusculaire, Institut de Myologie, Groupe Hospitalier Universitaire La Pitié-Salpêtrière; Paris, France.
authors.forename: Maud
authors.initials: M
authors.lastname: Beuvin
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, GH Pitié-Salpêtrière, 47 Boulevard de l'hôpital, 75013 Paris, France.|Unité de Morphologie Neuromusculaire, Institut de Myologie, Groupe Hospitalier Universitaire La Pitié-Salpêtrière; Paris, France.|Centre de référence de Pathologie Neuromusculaire Paris-Est, Institut de Myologie, GHU La Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris; Paris, France.
authors.forename: Norma B
authors.initials: NB
authors.lastname: Romero
authors.affiliation: Department of Translational Medecine, IGBMC, Illkirch, France.|INSERM U964, Illkirch, France.|CNRS, UMR7104, Illkirch, France.|Strasbourg University, Illkirch, France.
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Laporte
keywords: Congenital myopathy; MYO18B; cardiomyopathy; myosin; nemaline myopathy