Clustered 11q23 and 22q11 breakpoints and 3:1 meiotic malsegregation in multiple unrelated t(11;22) families
| Autor: | Beverly S. Emanuel, Elaine H. Zackai, Livija Celle, Marcia L. Budarf, Tamim H. Shaikh |
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| Rok vydání: | 1999 |
| Předmět: |
Genetic Markers
Male Heterozygote Duplication Chromosomes Human Pair 22 Molecular Sequence Data Translocation Breakpoint Chromosome 22q11 Chromosomal translocation Biology Malsegregation Translocation Genetic Nondisjunction Genetic Genetics Chromosome 11q23 Humans Genetics(clinical) Cloning Molecular Genetics (clinical) Alleles In Situ Hybridization Fluorescence Family Health Polymorphism Genetic Chromosomes Human Pair 11 Breakpoint Physical Chromosome Mapping Chromosome Breakage Syndrome Articles Meiosis Nondisjunction t(11 22) Translocation breakpoint Female Chromosome breakage Chromosome 21 DNA Probes Chromosome 22 |
| Zdroj: | American journal of human genetics. 65(6) |
| ISSN: | 0002-9297 |
| Popis: | The t(11;22) is the only known recurrent, non-Robertsonian constitutional translocation. We have analyzed t(11;22) balanced-translocation carriers from multiple unrelated families by FISH, to localize the t(11;22) breakpoints on both chromosome 11 and chromosome 22. In 23 unrelated balanced-translocation carriers, the breakpoint was localized within a 400-kb interval between D22S788 (N41) and ZNF74, on 22q11. Also, 13 of these 23 carriers were tested with probes from chromosome 11, and, in each, the breakpoint was localized between D11S1340 and APOA1, on 11q23, to a region ⩽185 kb. Thus, the breakpoints on both chromosome 11 and chromosome 22 are clustered in multiple unrelated families. Supernumerary-der(22)t(11;22) syndrome can occur in the progeny of balanced-t(11;22) carriers, because of malsegregation of the der(22). There has been speculation regarding the mechanism by which the malsegregation occurs. To elucidate this mechanism, we have analyzed 16 of the t(11;22) families, using short tandem-repeat–polymorphism markers on both chromosome 11 and chromosome 22. In all informative cases the proband received two of three alleles, for markers above the breakpoint on chromosome 22 and below the breakpoint on chromosome 11, from the t(11;22)-carrier parent. These data strongly suggest that 3:1 meiosis I malsegregation in the t(11;22) balanced-translocation–carrier parent is the mechanism in all 16 families. Taken together, these results establish that the majority of t(11;22) translocations occur within the same genomic intervals and that the majority of supernumerary-der(22) offspring result from a 3:1 meiosis I malsegregation in the balanced-translocation carrier. |
| Databáze: | OpenAIRE |
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