MECP2 mutation analysis in patients with mental retardation.
Mutations in the methyl-CpG-binding protein 2 (MECP2) gene are known to underlie Rett' syndrome, the most common cause of mental retardation (MR) in girls. Since the original report, phenotypes resulting from MECP2 mutations have been shown to extend, for example, to several Rett variants, autism, atypical Angelman syndrome, and nonspecific MR. It was earlier proposed that MECP2 mutations might account for approximately 2% of the male cases with nonspecific MR. Thereby, the frequency of MECP2 mutations in the mentally retarded population would be comparable to that of Fragile-X syndrome. The aim of this study was to analyze well-characterized cases with MR and to clarify the role of the MECP2 gene in the etiology of MR and atypical Angelman syndrome. The coding sequence of the MECP2 gene was analyzed in a sample of 118 patients (103 males, 15 females) by direct sequencing. Two coding sequence variants, 602C > T (A201V) and 1189G > A (E397K), were identified. In addition, we identified four variants in the intronic or 3'UTR regions. None of these variants is likely to be causal. We conclude that the evidence across all the mutation screening studies implies that MECP2 mutations do not represent a major cause of nonspecific MR.
Ylisaukko-Oja
Tero
T
Department of Molecular Medicine, National Public Health Institute, Helsinki, Finland. tero.ylisaukko-oja@ktl.fi
Rehnström
Karola
K
Vanhala
Raija
R
Kempas
Elli
E
von Koskull
Harriet
H
Tengström
Carola
C
Mustonen
Aki
A
Ounap
Katrin
K
Lähdetie
Jaana
J
Järvelä
Irma
I
D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics*; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics* / Q000473:pathology; D008297:Male; D051783:Methyl-CpG-Binding Protein 2; D009154:Mutation; D020125:Mutation, Missense; D017354:Point Mutation; D012097:Repressor Proteins / Q000235:genetics*
D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; C497392:MECP2 protein, human; D051783:Methyl-CpG-Binding Protein 2; D012097:Repressor Proteins; D004247:DNA