title: Mosaic imprinting defect in a patient with an almost typical expression of the Prader-Willi syndrome.
abstract: We describe a young woman with Prader-Willi syndrome (PWS) due to a mosaic imprinting defect. Three independent assays revealed a reduced proportion of nonmethylated SNURF-SNRPN alleles in peripheral blood DNA: methylation-specific PCR followed by denaturing high-performance liquid chromatography (MSP/DHPLC), methylation-sensitive restriction enzyme analysis and methylation-specific real-time PCR analysis. Microsatellite analysis and fluorescence in situ hybridisation revealed apparently normal chromosomes 15 of biparental origin. Based on the MSP/DHPLC and real-time PCR results, we estimate that approximately 50% of the patient's blood cells have an imprinting defect and 50% of the cells are normal. Apart from a rather normal facial appearance, the proband has typical features of PWS.
authors.affiliation: Institute of Medical Genetics, University of Zurich, Switzerland.
authors.forename: Eva
authors.initials: E
authors.lastname: Wey
authors.forename: Deborah
authors.initials: D
authors.lastname: Bartholdi
authors.forename: Mariluce
authors.initials: M
authors.lastname: Riegel
authors.forename: Hülya
authors.initials: H
authors.lastname: Nazlican
authors.forename: Bernhard
authors.initials: B
authors.lastname: Horsthemke
authors.forename: Albert
authors.initials: A
authors.lastname: Schinzel
authors.forename: Alessandra
authors.initials: A
authors.lastname: Baumer
mesh_terms: D000328:Adult; D002648:Child; D002851:Chromatography, High Pressure Liquid; D019175:DNA Methylation; D005260:Female; D018392:Genomic Imprinting; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D018895:Microsatellite Repeats; D009030:Mosaicism; D016133:Polymerase Chain Reaction; D011218:Prader-Willi Syndrome / Q000235:genetics*