Insights from genotype–phenotype correlations by novel SPEG mutations causing centronuclear myopathy

Haicui Wang, Claudia Castiglioni, Ayşe Kaçar Bayram, Fabiana Fattori, Serdar Pekuz, Diego Araneda, Hüseyin Per, Ricardo Erazo, Hakan Gümüş, Suzan Zorludemir, Kerstin Becker, Ximena Ortega, Jorge Alfredo Bevilacqua, Enrico Bertini, Sebahattin Cirak

Research output: Contribution to journalArticlepeer-review


Centronuclear myopathies (CNM) are a clinically and genetically heterogeneous group of congenital myopathies, defined histologically by increased number of fibres with centrally located nuclei, and type I fibre predominance in muscle biopsy. Myotubular myopathy, the X-linked form of CNM caused by mutations in the phosphoinositide phosphatase MTM1, is histologically characteristic since muscle fibres resemble myotubes. Here we present two unrelated patients with CNM and typical myotubular fibres in the muscle biopsy caused by mutations in striated muscle preferentially expressed protein kinase (SPEG). Next generation sequencing revealed novel biallelic homozygous mutations in SPEG in both cases. Patient 1 showed the c.1627_1628insA (p.Thr544Aspfs*48) mutation and patient 2 the c.9586C>T (p.Arg3196*) mutation. The clinical phenotype was distinctive in the two patients since patient 2 developed a dilated cardiomyopathy with milder myopathy features, while patient 1 showed only myopathic features without cardiac involvement. These findings expand the genotype–phenotype correlations after the initial report. Additionally, we describe whole body muscle MRI of patient 2 and we argue on the different SPEG isoforms in skeletal muscle and heart as the possible explanation leading to variable phenotypes of SPEG mutations.

Original languageEnglish
Pages (from-to)836-842
Number of pages7
JournalNeuromuscular Disorders
Issue number9
Publication statusPublished - Sep 1 2017


  • Centronuclear myopathy
  • Exome
  • Myotubular myopathy
  • SPEG
  • Whole body MRI

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Neurology
  • Clinical Neurology
  • Genetics(clinical)


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