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GENATLAS PHENOTYPE
last update : 06-12-2016
Symbol DMD
Location Xp21.1
Name muscular dystrophy, Duchenne or type
Other name(s) muscular dystrophy, pseudohypertrophic progressive
Corresponding gene DMD
related resource Becker
Other symbol(s) MDD
Main clinical features
  • progressive proximal muscular dystrophy with characteristic pseudohypertrophy of the calves, sparing the bulbar (extraocular) muscles but the myocardium is affected; massive elevation of creatine kinase levels in the blood, myopathic changes by electromyography, and myofiber degeneration with fibrosis and fatty infiltration on muscle biopsy
  • diagnosis in infancy ( median 4.6 years), wheelchair dependency had a median age of 10 years, cardiac muscle failure developed in 15p100 of patients with a median age of 21.5 years
  • sometimes associated to mental retardation of mild degree, and abnormal retinal neurotransmission as measured by electroretinography (ERG) with abnormal red-green color vision
    • Genetic determination sex linked
    Prevalence 1 in 3,500 live male births (PMID: 20696926)
    Function/system disorder neuromuscular
    Type disease
    Gene product
    Name dystrophin (DMD)
    Mechanism(s)
    Gene mutationChromosome rearrangementEffectComments
    various types   absent protein In general, DMD patients carry mutations which cause premature translation termination (nonsense or frame shift mutations)
    Remark(s)
  • two-amino acid mutation encountered in Duchenne Muscular Dystrophy decreases stability of the rod domain 23 (R23) spectrin-like repeat (Legardinier 2009)
  • mutations upstream to exon 62, with DMD phenotype, predicted to lead to a loss-of-function of all dystrophin products, except Dp71 isoform, are associated, predominantly, with normal or borderline cognitive performance (Daoud 2009)
  • more than 50p100 of missense mutations that trigger the disease occur in the N-terminal actin binding domain (N-ABD), decreasing its thermodynamic stability and increasing its misfolding, thereby decreasing the net functional dystrophin concentration,and leading to aggregation during the folding process (PMID: 20696926)), (PMID: 20457930))
  • reduced CD40-mediated cell-cell signaling in carriers of the minor rs1883832 allele might precipitate failure of regeneration and fibrosis in DMD skeletal muscle (PMID: 27745838))
    • Genotype/Phenotype correlations impairment related to dystrophin isoform Dp260 leads to red-green color defect