Mitotic recombination and uniparental disomy in Beckwith-Wiedemann syndrome.
Beckwith-Wiedemann syndrome (BWS) is a model human imprinting disorder resulting from altered activity of one or more genes in the 11p15.5 imprinted gene cluster. Approximately 20% of BWS cases have uniparental disomy (UPD) of chromosome 11. Such cases appear to result from mitotic recombination occurring in early embryogenesis and offer a rare opportunity to study mitotic recombination in nonneoplastic cells. We analyzed a cohort of 52 children with BWS and UPD using a panel of microsatellite markers for chromosome 11. All cases demonstrated mosaic paternal isodisomy, and IGF2 and H19 were included in the segment of UPD in all cases. However, the extent of segmental disomy was variable, with no evidence of clustering of the proximal UPD breakpoint. In most cases (92% of those informative) UPD did not involve 11q, but 4 patients demonstrated UPD for the whole of chromosome 11. In contrast to meiotic recombination, the mitotic recombination frequency did not decline near the centromere.
Cooper
Wendy N
WN
Department of Medical and Molecular Genetics, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK.
Curley
Rebecca
R
Macdonald
Fiona
F
Maher
Eamonn R
ER
D001506:Beckwith-Wiedemann Syndrome / Q000235:genetics*; D002648:Child; D002880:Chromosomes, Human, Pair 11; D019175:DNA Methylation; D018392:Genomic Imprinting; D006801:Humans; D008938:Mitosis / Q000235:genetics*; D011995:Recombination, Genetic; D024182:Uniparental Disomy / Q000235:genetics*