Predictive diagnosis of the cancer prone Li–Fraumeni syndrome by accident: new challenges through whole genome array testing

BACKGROUND Li-Fraumeni syndrome greatly increases the risk of developing several types of cancer and is usually caused by TP53 germline mutations. Predictive testing of at-risk family members is only offered after a complex genetic counselling process. Recently the clinical implementation of array comparative genomic hybridisation (CGH) has revolutionised the diagnosis of patients with syndromic or non-syndromic mental retardation and has evolved to a routinely performed high resolution whole genome scan. METHODS AND RESULTS When using array CGH to identify the cause for mental retardation in a 7-year-old child we found a submicroscopic de novo deletion of chromosome 17p13.1, which includes several genes likely to be causative for her phenotype, and also of TP53. CONCLUSION Thus, array CGH resulted in an unintended predictive diagnosis of an increased tumour susceptibility as observed in Li-Fraumeni syndrome.