Impact of low copy repeats on the generation of balanced and unbalanced chromosomal aberrations in mental retardation.
Cytogenet Genome Res
; 115(3-4): 247-53, 2006.
Article
em En
| MEDLINE
| ID: mdl-17124407
ABSTRACT
Low copy repeats (LCRs) are stretches of duplicated DNA that are more than 1 kb in size and share a sequence similarity that exceeds 90%. Non-allelic homologous recombination (NAHR) between highly similar LCRs has been implicated in numerous genomic disorders. This study aimed at defining the impact of LCRs on the generation of balanced and unbalanced chromosomal rearrangements in mentally retarded patients. A cohort of 22 patients, preselected for the presence of submicroscopic imbalances, was analysed using submegabase resolution tiling path array CGH and the results were compared with a set of 41 patients with balanced translocations and breakpoints that were mapped to the BAC level by FISH. Our data indicate an accumulation of LCRs at breakpoints of both balanced and unbalanced rearrangements. LCRs with high sequence similarity in both breakpoint regions, suggesting NAHR as the most likely cause of rearrangement, were observed in 6/22 patients with chromosomal imbalances, but not in any of the balanced translocation cases studied. In case of chromosomal imbalances, the likelihood of NAHR seems to be inversely related to the size of the aberration. Our data also suggest the presence of additional mechanisms coinciding with or dependent on the presence of LCRs that may induce an increased instability at these chromosomal sites.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Aberrações Cromossômicas
/
Duplicação Gênica
/
Deficiência Intelectual
Tipo de estudo:
Etiology_studies
/
Incidence_studies
/
Observational_studies
/
Risk_factors_studies
Limite:
Humans
Idioma:
En
Revista:
Cytogenet Genome Res
Ano de publicação:
2006
Tipo de documento:
Article