Classic Rett syndrome in a boy with R133C mutation of MECP2

Brain Dev. 2005 Sep;27(6):439-42. doi: 10.1016/j.braindev.2004.10.002.


About 80% of female patients with Rett syndrome (RTT) display a mutation in the methyl-CpG-binding protein 2 (MECP2) gene, but most males with MECP2 mutation experience severe fatal encephalopathy or non-specific X-linked mental retardation (XLMR). The existence of male RTT has been extensively discussed. We report herein a boy with classic RTT in a family with a missense mutation in MECP2. The mother exhibited slight mental retardation and was a carrier for R133C. The patient could stand with support at 12-months-old, and stereotypic hand movements appeared at 3-years-old. He became bed-ridden by 8-years-old. The R133C mutation was present in MECP2 without somatic mosaicism. A sister with R133C displayed classic RTT. The R133C mutation has been detected in female patients with classic and preserved speech variant RTT, but not in males with non-specific XLMR. These results suggest that clinical phenotypes caused by DNA mutation in MECP2 are determined by position of the mutation in the gene, and R133 represents a critical amino acid residue in the induction of RTT symptoms in humans.

Publication types

  • Case Reports

MeSH terms

  • Child
  • Chromosomal Proteins, Non-Histone / genetics*
  • DNA-Binding Proteins / genetics*
  • Family Health
  • Humans
  • Male
  • Methyl-CpG-Binding Protein 2
  • Point Mutation*
  • Repressor Proteins / genetics*
  • Rett Syndrome / genetics*


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