Molecular cytogenetic evidence for a common breakpoint in the largest inverted duplications of chromosome 15.
Chromosomes from 20 patients were used to delineate the breakpoints of inverted duplications of chromosome 15 (inv dup[15]) that include the Prader-Willi syndrome/Angelman syndrome (PWS/AS) chromosomal region (15q11-q13). YAC and cosmid clones from 15q11-q14 were used for FISH analysis, to detect the presence or absence of material on each inv dup(15). We describe two types of inv dup(15): those that break between D15S12 and D15S24, near the distal boundary of the PWS/AS chromosomal region, and those that share a breakpoint immediately proximal to D15S1010. Among the latter group, no breakpoint heterogeneity could be detected with the available probes, and one YAC (810f11) showed a reduced signal on each inv dup(15), compared with that on normal chromosomes 15. The lack of breakpoint heterogeneity may be the result of a U-type exchange involving particular sequences on either homologous chromosomes or sister chromatids. Parent-of-origin studies revealed that, in all the cases analyzed, the inv dup(15) was maternal in origin.
Wandstrat
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AE
Department of Genetics, Case Western Reserve University School of Medicine, and Center for Human Genetics, University Hospitals of Cleveland, Cleveland, OH, USA.
Leana-Cox
J
J
Jenkins
L
L
Schwartz
S
S
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D018244:Chromosomes, Artificial, Yeast; D002884:Chromosomes, Human, Pair 15; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D005810:Multigene Family; D011218:Prader-Willi Syndrome / Q000235:genetics*