Abstract Objective To study the clinical features and mutations in methyl-CpG-binding protein 2 (MECP2) gene among children with classical Rett syndrome in China. Methods PCR and direct sequencing were employed to analyze the three exons of MECP2 gene in 9 children recently diagnosed with Rett syndrome and their parents. Results Heterozygous mutations were identified in 5 out of 9 patients, with a mutation rate of over 50%; there was one case of insert mutation (c.913insT) and 4 cases of missense mutation (exon 3: c.316C>T (R106W); exon 4: c.502C>T (R168X), c.808C>T (R270X), and c.1126C>T (P376S)). A new mutation (c.913insT) was found. No mutations were detected in their parents. Two patients had MECP2 mutations in the transcriptional repression domain (TRD). They had almost lost language functions and were found to have significantly delayed development compared with other patients. Conclusions Mutations in MECP2 gene were detected in 5 confirmed cases of Rett syndrome, and most of them were on exon 4. Mutations in the TRD of MECP2 protein may affect the language ability and development in children with Rett syndrome.
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