Imprinting mutations suggested by abnormal DNA methylation patterns in familial Angelman and Prader-Willi syndromes. |
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| Authors: | A. Reis B. Dittrich V. Greger K. Buiting M. Lalande G. Gillessen-Kaesbach M. Anvret B. Horsthemke |
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| Affiliation: | Institut für Humangenetik, Freie Universität, Berlin. |
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| Abstract: | ![]()
The D15S9 and D15S63 loci in the Prader-Willi/Angelman syndrome region on chromosome 15 are subject to parent-of-origin-specific DNA methylation. We have found two Prader-Willi syndrome families in which the patients carry a maternal methylation imprint on the paternal chromosome. In one of these families, the patients have a small deletion encompassing the gene for the small nuclear ribonucleoprotein polypeptide N, which maps 130 kb telomeric to D15S63. Furthermore, we have identified a pair of nondeletion Angelman syndrome sibs and two isolated Angelman syndrome patients who carry a paternal methylation imprint on the maternal chromosome. These Angelman and Prader-Willi syndrome patients may have a defect in the imprinting process in 15q11-13. We propose a model in which a cis-acting mutation prevents the resetting of the imprinting signal in the germ line and thus disturbs the expression of imprinted genes in this region. |
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