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GENATLAS PHENOTYPE
last update : 08/10/2008
Symbol RTTM
Location Xq28
Name MECP2-related disorders in males
Other name(s)
  • MECP2-related encephalopathy neonatal severe
  • mental retardation, X-linked, with progressive spasticity
    • Corresponding gene MECP2
    Main clinical features three main categories:
  • severe neonatal encephalopathy, and infantile death,
  • symptoms similar to classical RTT in XXY or mosaic patients,
  • less severe neurological and/or psychiatric manifestations
    • Genetic determination sex linked
    Prevalence between 1.3 and 1.7 percent in mentally retarded male patients
    Related entries RTT, DUPXQ28
    Function/system disorder neuromuscular
    mental retardation
    Type MCA/MR
    Mechanism(s)
    Gene mutationChromosome rearrangementEffectComments
    various types     among which A140V, in the MBD domain , in group 3, not described in classic RTT girls
    various types     R133H in the MBD domain or R270X in the TRD domain and others in Rett-like syndrome (group 2)
    various types     G269fs,T158M and others in severe congenital encephalopthy (group 1)
    duplication     of MECP2 and variable adjacent region
    Remark(s)
    Genotype/Phenotype correlations
  • changes in the WW domain only affecting the males, with mild to severe mental retardation
  • changes in the TRD or MBD domain in Rett-like or in severe encephalopathy
  • MECP2 null mutation display a phenotype of severe neonatal-onset encephalopathy with central hypoxia and reduced neuronal dendritic structure