Progress towards mapping the constitutional t(11:22) breakpoint
- Children`s Hospital of Philadelphia, PA (United States); and others
The reciprocal t(11;22)(q23;q11) is the most frequent, recurrent, non-Robertsonian, constitutional translocation in humans. Balanced carriers of this rearrangement are phenotypically normal, but are at risk for producing abnormal offspring with the Supernumerary der(22)t(11;22) Syndrome. Further, a recent report of association between t(11;22) balanced translocation carriers and breast cancer, suggests the involvement of genes on 11q and/or 22q in breast cancer tumorigenesis. Studies are in progress to examine the similarity between 11q23 and 22q11 breakpoints in multiple families with the constitutional t(11;22). A 750 kb YAC, which contains markers known to flank the 11q23 breakpoint, was identified in CEPH/Genethon database. FISH with this YAC to two independent t(11;22) cell lines demonstrates signal on both derivative chromosomes. Numerous YACs containing BCRL2, the closest marker proximal to the breakpoint, were identified. Analysis of these YACs to determine which contain the actual breakpoint sequences is complicated by the presence of a duplicated segment of 22q11 which contains a GGTL and a BCRL locus. Sequences homologous to these loci are present at several other locations in 22q11. The BCRL positive YACs were analyzed by Southern hybridization under conditions which distinguish the four members of the BCR/BCRL family. FISH of total yeast DNA plus YAC DNA labeled by nick translation, or biotin-labeled inter-Alu PCR products confirmed the localization of these YACs to 22q11. Additional FISH with these YACS to metaphase spreads prepared from balanced t(11;22) carriers confirm that these clones span the breakpoint, and will allow rapid isolation and definition of the genetic region adjacent to the t(11;22) breakpoint.
- OSTI ID:
- 133303
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-0030
- Journal Information:
- American Journal of Human Genetics, Vol. 55, Issue Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
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