Unexpected findings in cancer predisposition genes detected by array comparative genomic hybridisation: what are the issues?

Objective To calculate and discuss the percentage of imbalance for selected cancer predisposition genes in patients referred for routine diagnostic array comparative genomic hybridisation (CGH). Design Audit of findings from application of array CGH for patients referred for developmental delay, behavioural abnormalities and birth defects in 4805 patients referred to Guy9s and St Thomas9 NHS Foundation Trust for cytogenetic investigation from South East London, Kent and East Sussex and other genetic centres across the UK. Results 29 of 4805 (0.6%) patients examined by array CGH had genomic imbalance of Conclusions This new technology raises the possibility of unexpected findings in cancer predisposition genes. Therefore, the possibility of such findings has to be addressed in pre-test and post-test counselling by genetically trained healthcare professionals. As many of these findings have not been described previously, their clinical significance is unknown and patients need long-term follow-up to determine their clinical relevance. This will enable genetic healthcare professionals to advise such people about their cancer risks and appropriate cancer risk management options.