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  • Cited by 1
  • Print publication year: 2002
  • Online publication date: August 2009

9 - Prader-Willi and Angelman syndromes: from childhood to adult life


The Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are two distinct syndromes that have in common either deletion at the locus 15q11.2 or the presence of genetic abnormalities of chromosome 15. PWS is likely to be a contiguous gene syndrome in which the failure of expression of specific maternally imprinted genes is of aetiological significance. In contrast, AS has been shown to be due to the loss of expression of a single paternally imprinted gene. This may occur because of a mutation affecting UB3EA, the deletion of the maternal copy of that gene, or the presence of a paternal chromosome 15 disomy. This genetic map is illustrated in this chapter. PWS and AS have illustrated the importance of a specific genetic mechanism on human development and how the expression or not of specific imprinted gene(s) has radically different effects on development and behaviour.