An atypical case of hypomethylation at multiple imprinted loci

Emma Louise Baple (1) , Rebecca Louise Poole (1) , Sahar Mansour (1) , Catherine Willoughby (1) , I. Karen Temple (1) , Louise Docherty (1) , Rohan Taylor (1) , Deborah Jg Mackay (1)

1 Medical Genetics Unit

Angelman syndrome (AS) and Prader-Willi syndrome (PWS) are caused by genetic and epigenetic mutations of the imprinted gene cluster on chromosome 15q13. Although the imprinting mutations causing PWS and AS are essentially opposite in nature, remarkably, a small number of patients have been reported with clinical features of PWS but epigenetic mutations consistent with AS. We report here a patient who presented with clinical features partially consistent with both PWS and BWS (Beckwith-Wiedemann syndrome). Epimutations were found at both the AS/PWS and BWS loci, and additionally at the H19, PEG3, NESPAS and GNAS loci. This patient is therefore the first described case with a primary epimutation consistent with AS accompanied by hypomethylation of other imprinted loci (AS-HIL).

Mots clés: Angelman; Prader-Willi; Beckwith-Wiedemann

Emma Louise Baple, Rebecca Louise Poole, Sahar Mansour, Catherine Willoughby, I. Karen Temple, et al.. An atypical case of hypomethylation at multiple imprinted loci. European Journal of Human Genetics, 2010, ⟨10.1038/ejhg.2010.218⟩. ⟨hal-00602292⟩