title: Angelman syndrome associated with a maternal 15q11-13 deletion of less than 200 kb.
abstract: Angelman syndrome (AS) is a neurogenetic disorder arising from a lack of genetic contribution from the maternal chromosome 15q11-13. To date, the AS critical region has been defined by an inherited deletion of approximately 1.5Mb, spanning the 3-21 (D15S10), LS6-1 (D15S113) and GABRB3 loci. We have identified an individual with the typical features of AS who has a deletion of the maternal chromosome which encompasses LS6-1, but does not extend to either flanking marker. This deletion, initially detected by (CA)n repeat analysis, was further characterised by fluorescence in situ hybridisation (FISH) using cosmids derived from a 260 kb LS6-1 yeast artificial chromosome (YAC). Neither end cosmid from this YAC clone falls within the deletion, suggesting that the minimal AS region is less than 200 kb. We also studied three loci within 15q11-13 which detect parent-of-origin specific DNA methylation imprints, and found that both normal maternal and paternal patterns were present in this patient.
authors.affiliation: Unit of Molecular Genetics, Institute of Child Health, London, UK.
authors.forename: J L
authors.initials: JL
authors.lastname: Buxton
authors.forename: C T
authors.initials: CT
authors.lastname: Chan
authors.forename: H
authors.initials: H
authors.lastname: Gilbert
authors.forename: J
authors.initials: J
authors.lastname: Clayton-Smith
authors.forename: J
authors.initials: J
authors.lastname: Burn
authors.forename: M
authors.initials: M
authors.lastname: Pembrey
authors.forename: S
authors.initials: S
authors.lastname: Malcolm
mesh_terms: D017204:Angelman Syndrome / Q000235:genetics*; D002675:Child, Preschool; D002872:Chromosome Deletion; D002874:Chromosome Mapping; D002884:Chromosomes, Human, Pair 15; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D012091:Repetitive Sequences, Nucleic Acid