055 Audit of the use of array CGH in epilepsy patients seen at a tertiary clinic
Microdeletions or duplications, also known as copy number variants (CNVs), identified using array comparative genome hybridisation (array CGH) constitute the commonest known genetic cause of the epilepsies. Yet, this technique remains underutilised in most clinical services. We audited the yield of array CGH in a tertiary epilepsy clinic before mid August 2010. Until then, this test was only requested in selected cases with epilepsy of unknown aetiology, where there was also a personal or family history of learning difficulty, developmental delay or mental health problems including autism. CGH array was performed in 30 cases in this time period. Three with 15q13.3 microdeletion were related to a previously diagnosed case and are thus excluded from the results. In remaining 27 cases the findings were as follows. In 17 (63%) no abnormality was found. In 3 (11%) an imbalance of uncertain significance was detected and was considered most likely a ‘benign variant’. In 7 (26%) significant changes were found, sometimes more than one variant per individual. These included variants in 1p22.1, 7q35, 15q11.2 (detected in 2 cases), 15q13.1, 15q13.2 (3 cases), 16p12.1, 16q13.11 and 17q12. Our results indicate the usefulness of this test in this setting. Identifying underlying genetic susceptibility has value not only in determining the aetiology and aiding clinical management but also in genetic counselling.