Rett syndrome in a boy with a 47,XXY karyotype confirmed by a rare mutation in the MECP2 gene

Neuropediatrics. 2001 Jun;32(3):162-4. doi: 10.1055/s-2001-16620.


Rett syndrome (RTT) is an X-linked condition which affects almost exclusively females. Here we report the first case of RTT syndrome in a boy with an XXY chromosomal constitution. Mutation analysis of the MECP2 gene in the affected patient revealed a 423 C-->G substitution in exon 4, resulting in a new stop codon (Y141 X). This change was not present in both his parents or in his older sister. Taking into account the incidence of both RTT syndrome as well as of Klinefelter syndrome, the probability for the simultaneous occurrence of these two events is very low (about approximately 1 in 10 to 15,000,000 births). However, the recent identification of mutations in the MECP2 gene in affected males indicates that screening of the MECP2 gene should be considered also in males with severe mental retardation (MR) in whom the most common forms of MR have been excluded.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Child, Preschool
  • Chromosomal Proteins, Non-Histone*
  • DNA Mutational Analysis
  • DNA-Binding Proteins / genetics*
  • Exons
  • Genetic Testing
  • Humans
  • Intellectual Disability / diagnosis
  • Intellectual Disability / genetics
  • Klinefelter Syndrome / diagnosis
  • Klinefelter Syndrome / genetics*
  • Male
  • Methyl-CpG-Binding Protein 2
  • Molecular Sequence Data
  • Mutation / genetics*
  • Repressor Proteins*
  • Rett Syndrome / diagnosis
  • Rett Syndrome / genetics*


  • Chromosomal Proteins, Non-Histone
  • DNA-Binding Proteins
  • MECP2 protein, human
  • Methyl-CpG-Binding Protein 2
  • Repressor Proteins

Associated data

  • GENBANK/X99686
  • OMIM/312750