Mental retardation in a girl with a subtelomeric deletion on chromosome 20q and complete deletion of the myelin transcription factor 1 gene (MYT1)

Clin Genet. 2008 May;73(5):492-5. doi: 10.1111/j.1399-0004.2008.00982.x. Epub 2008 Mar 12.


A great number of syndromes and inborn errors of metabolism associated with impaired development have been observed, but the aetiology of mental retardation remains unclear in a considerable proportion of cases. Here, we present the clinical and molecular data from a patient with a new de novo subtelomeric deletion on chromosome 20 [46,XX.ish del(20)(qter-)]. For further refinement, bacterial artificial chromosome clones are used. The deletion spans exactly two genes called MYT1 and PCMTD2. Both genes play an important role in myelination and regulating neural differentiation. Loss of these two genes seems to be responsible for the severe mental retardation and mild facial dysmorphic features in our young patient. It might show the phenotypic picture of this specified deletion.

MeSH terms

  • Child, Preschool
  • Chromosome Deletion*
  • Chromosomes, Human, Pair 20 / genetics*
  • DNA-Binding Proteins / deficiency
  • Female
  • Humans
  • Intellectual Disability / genetics*
  • Telomere / genetics*
  • Transcription Factors / deficiency


  • DNA-Binding Proteins
  • MYT1 protein, human
  • Transcription Factors