FIGURE 6.

Genetic characteristics of Prader-Willi Syndrome (PWS) and Angelman Syndrome (AS). Approximately 65%–70% of PWS cases result from the deletion of genetic material in the paternal copy of chromosome 15, 20%–30% of PWS cases result from maternal disomy, and 1%–3% of PWS cases result from imprinting mutations in genomic regions associated with imprinting control on the paternal chromosome 15 (Cassidy et al., 2012). Meanwhile, approximately 90% of AS cases result from the deletion of genetic material in the maternal copy of chromosome 15, 3%–7% of AS cases result from paternal disomy, and 2%–4% of AS cases result from imprinting mutations in genomic regions associated with imprinting control on the maternal chromosome 15 (Dagli et al., 2012).