title: An atypical case of hypomethylation at multiple imprinted loci.
abstract: 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 Beckwith-Wiedemann syndrome (BWS). 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.
authors.affiliation: SW Thames Regional Genetics Service, St George's NHS Trust, London, UK. ebaple@sgul.ac.uk
authors.forename: Emma L
authors.initials: EL
authors.lastname: Baple
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Poole
authors.forename: Sahar
authors.initials: S
authors.lastname: Mansour
authors.forename: Catherine
authors.initials: C
authors.lastname: Willoughby
authors.forename: I Karen
authors.initials: IK
authors.lastname: Temple
authors.forename: Louise E
authors.initials: LE
authors.lastname: Docherty
authors.forename: Rohan
authors.initials: R
authors.lastname: Taylor
authors.forename: Deborah J G
authors.initials: DJ
authors.lastname: Mackay
mesh_terms: D017204:Angelman Syndrome / Q000235:genetics*; D001506:Beckwith-Wiedemann Syndrome / Q000235:genetics*; D002675:Child, Preschool; D019175:DNA Methylation; D057890:Epigenomics; D005260:Female; D056426:Genetic Loci; D018392:Genomic Imprinting; D006801:Humans; D005810:Multigene Family; D009154:Mutation; D011218:Prader-Willi Syndrome / Q000235:genetics*