Classic Rett syndrome in a boy with R133C mutation of MECP2.
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.
Masuyama
Tatsuo
T
Department of Pediatrics, Faculty of Medicine, Saga University, Saga, Japan. ssgmasubb@yahoo.co.jp
Matsuo
Muneaki
M
Jing
Jin J
JJ
Tabara
Yasuharu
Y
Kitsuki
Kyoko
K
Yamagata
Hidehisa
H
Kan
Yuka
Y
Miki
Tetsuro
T
Ishii
Kiyohisa
K
Kondo
Ikuko
I
D002648:Child; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D005192:Family Health; D006801:Humans; D008297:Male; D051783:Methyl-CpG-Binding Protein 2; D017354:Point Mutation; D012097:Repressor Proteins / Q000235:genetics*; D015518:Rett Syndrome / Q000235:genetics*
D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; C497392:MECP2 protein, human; D051783:Methyl-CpG-Binding Protein 2; D012097:Repressor Proteins