The test detects defective DNA repair in response to alkylating agents by screening for increased spontaneous and mutagen induced chromosome breakage. The primary mutagen used is Diepoxybutane (DEB) which we find gives the best discrimination between affected and unaffected individuals but Mitomycin C (MMC) testing is available on request.
Ataxia-telangiectasia and Nijmegen breakage syndrome patients are defective for repair of ionising radiation induced damage. Raised spontaneous and gamma ray induced chromosome breakage is screened for and G-banded metaphase preparations are examined for clonal chromosome rearrangements, particularly involving the immunoglobulin genes on chromosomes 7 and 14.
Our genetics laboratory is a supra-regional and international reference laboratory for chromosome instability testing by cytogenetic techniques: our experience encompasses the full range of classical and atypical cases reported in the literature. Specific testing strategies for the different disorders are employed to look for raised spontaneous and specific mutagen-induced damage and/or chromosome rearrangements or other anomalous behaviour. We offer both pre- and postnatal diagnosis on amniotic fluid, chorionic villi, blood and solid tissue samples.
Synonyms or keywords:
Chromosome breakage, chromosome instability, Fanconi anaemia, Diepoxybutane, DEB test, Mitomycin C, MMC, Radiosensitivity syndromes, Ataxia-telangiectasia, Nijmegen breakage syndrome, Bloom syndrome, Roberts syndrome, SC Phocomelia, Premature chromosome condensation, MCPH1, ICF syndrome, Werner syndrome, variegated aneuploidy syndrome