Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder, which almost exclusively affects girls, who, after an initial period of apparently normal development, display gradual loss of speech and purposeful hand use, gait abnormalities and stereotypical hand movements. In the year 2000, mutations in the gene for the methyl CpG binding protein 2, MECP2, have been identified in 35–80% of the patients in three different studies. We have identified 15 different MECP2 mutations in 26 of 30 Danish RTT patients. The mutations included five novel mutations (one point mutation, three smaller deletions involving identical regions in the gene, and one duplication). In contrast to the point mutations and the duplication, which all affect the methyl binding domain or the transcriptional repressing domain, the three overlapping deletions are clustered in the 3′ end of the gene. We found no consistent correlation between the type of mutation and the clinical presentation of the patient or the X-inactivation pattern in peripheral blood. Our high mutation detection rate, compared to two of the previous studies, underscores the importance of the inclusion criteria of the patients and supports that MECP2 is the most important, if not the only, gene responsible for RTT.
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Acknowledgements
We thank the patients and their parents for their participation, Bodil Mogensen for excellent technical assistance with the X chromosome inactivation investigation, and the staff at the J.F.Kennedy Institute. This work was supported by the Danish Biotechnological Research and Development Programme 1996–1998, The Danish Environmental Research Programme, the Danish Research Councils (9700832), the Danish Cancer Society, Novo Nordisk Foundation, Aage Bangs Foundation, Deutche Bundesministerium für Forschung und Technologie (01KW99087) and the EU-Commission (BMH4-CT97-2268).
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Nielsen, J., Henriksen, K., Hansen, C. et al. MECP2 mutations in Danish patients with Rett syndrome: High frequency of mutations but no consistent correlations with clinical severity or with the X chromosome inactivation pattern. Eur J Hum Genet 9, 178–184 (2001). https://doi.org/10.1038/sj.ejhg.5200600
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DOI: https://doi.org/10.1038/sj.ejhg.5200600
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