title: Genomic inversions of human chromosome 15q11-q13 in mothers of Angelman syndrome patients with class II (BP2/3) deletions.
abstract: Parental submicroscopic genomic inversions have recently been demonstrated to be present in several genomic disorders. These inversions are genomic polymorphisms that facilitate misalignment and abnormal recombination between flanking segmental duplications. Angelman syndrome (AS; MIM 105830) is associated with specific abnormalities of chromosome 15q11-q13, with about 70% of cases being mother-of-origin 4 Mb deletions. We present here evidence that some mothers of AS patients with deletions of the 15q11-q13 region have a heterozygous inversion involving the region that is deleted in the affected offspring. The inversion was detected in the mothers of four of six AS cases with the breakpoint 2-3 (BP2/3) 15q11-q13 deletion, but not in seven mothers of AS due to paternal uniparental disomy (UPD) 15. We have identified variable inversion breakpoints within BP segmental duplications in the inverted AS mothers, as well as in AS deleted patients. Interestingly, the BP2-BP3 region is inverted in the mouse draft genome sequence with respect to the human draft sequence. The BP2-BP3 chromosome 15q11-q13 inversion was detected in four of 44 subjects (9%) of the general population (P<0.004). The BP2/3 inversion should be an intermediate estate that facilitates the occurrence of 15q11-q13 BP2/3 deletions in the offspring.
authors.affiliation: Laboratorio di Citogenetica, Istituto G. Gaslini, Genoa, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Gimelli
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Pujana
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Patricelli
authors.forename: Silvia
authors.initials: S
authors.lastname: Russo
authors.forename: Daniela
authors.initials: D
authors.lastname: Giardino
authors.forename: Lidia
authors.initials: L
authors.lastname: Larizza
authors.forename: Joseph
authors.initials: J
authors.lastname: Cheung
authors.forename: Lluís
authors.initials: L
authors.lastname: Armengol
authors.forename: Albert
authors.initials: A
authors.lastname: Schinzel
authors.forename: Xavier
authors.initials: X
authors.lastname: Estivill
authors.forename: Orsetta
authors.initials: O
authors.lastname: Zuffardi
mesh_terms: D017204:Angelman Syndrome / Q000235:genetics*; D000818:Animals; D019457:Chromosome Breakage; D002872:Chromosome Deletion; D007446:Chromosome Inversion; D002884:Chromosomes, Human, Pair 15; D005260:Female; D006579:Heterozygote; D006801:Humans; D051379:Mice; D009035:Mothers