Genomic inversions of human chromosome 15q11-q13 in mothers of Angelman syndrome patients with class II (BP2/3) deletions.
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.
Gimelli
Giorgio
G
Laboratorio di Citogenetica, Istituto G. Gaslini, Genoa, Italy.
Pujana
Miguel Angel
MA
Patricelli
Maria Grazia
MG
Russo
Silvia
S
Giardino
Daniela
D
Larizza
Lidia
L
Cheung
Joseph
J
Armengol
Lluís
L
Schinzel
Albert
A
Estivill
Xavier
X
Zuffardi
Orsetta
O
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