Clinical and molecular consequences of exon 78 deletion in DMD gene

Monica Traverso, Stefania Assereto, Serena Baratto, Michele Iacomino, Marina Pedemonte, Maria Cristina Diana, Marta Ferretti, Paolo Broda, Carlo Minetti, Elisabetta Gazzerro, Francesca Madia, Claudio Bruno, Federico Zara, Chiara Fiorillo

Research output: Contribution to journalArticle

Abstract

We present a 13-year-old patient with persistent increase of serum Creatine Kinase (CK) and myalgia after exertion. Skeletal muscle biopsy showed marked reduction of dystrophin expression leading to genetic analysis of DMD gene by MLPA, which detected a single deletion of exon 78. To the best of our knowledge, DMD exon 78 deletion has never been described in literature and, according to prediction, it should lead to loss of reading frame in the dystrophin gene. To further assess the actual effect of exon 78 deletion, we analysed cDNA from muscle mRNA. This analysis confirmed the absence of 32 bp of exon 78. Exclusion of exon 78 changes the open reading frame of exon 79 and generate a downstream stop codon, producing a dystrophin protein of 3703 amino acids instead of 3685 amino acids. Albeit loss of reading frame usually leads to protein degradation and severe phenotype, in this case, we demonstrated that deletion of DMD exon 78 can be associated with a functional protein able to bind DGC complex and a very mild phenotype. This study adds a novel deletion in DMD gene in human and helps to define the compliance between maintaining/disrupting the reading frame and clinical form of the disease.

Original languageEnglish
Pages (from-to)761-764
Number of pages4
JournalJournal of Human Genetics
Volume63
Issue number6
DOIs
Publication statusPublished - Jun 2018

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Keywords

  • Adolescent
  • Biopsy
  • Codon, Terminator
  • Creatine Kinase/blood
  • DNA, Complementary/genetics
  • Dystrophin/genetics
  • Exons
  • Gene Deletion
  • Humans
  • Male
  • Muscle, Skeletal/pathology
  • Muscular Dystrophy, Duchenne/diagnosis
  • Myalgia/physiopathology
  • Open Reading Frames
  • Phenotype
  • RNA, Messenger/genetics

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