Abstracts

Rationale: Genetic testing is increasingly recognized as an important diagnostic tool in the evaluation of early life epilepsies and neurodevelopmental disorders. Traditional chromosome microarray (CMA) analysis identifies copy number variants and prior studies have demonstrated that approximately a quarter of individuals with autism spectrum disorders and epilepsy, among other factors, had an abnormal finding on microarray (Ezugha et al., 2010). Genome array is a next generation array technology that allows for increased resolution for smaller copy number variants, which are thought to contribute to the underlying pathophysiology of neurodevelopmental disorders such as autism spectrum disorder and epilepsy. Methods: All individuals were seen in the pediatric neurology clinic at Children’s Healthcare of Atlanta. Genome array genetic testing was offered to individuals who have not had prior chromosome microarray testing who have a diagnosis of autism spectrum disorder and epilepsy. Results: A total of 259 individuals within our department met criteria based on associated diagnoses. More than half (58%) individuals were excluded based on having a known genetic diagnosis as the explanation for their history or by having had a previous normal microarray genetic test. We contacted 108 individuals and offered a meeting with a genetic counselor to discuss genome array testing. Testing has been completed for 22 patients. Of these individuals, two have resulted in a diagnosis, Phelan McDermid syndrome and STXBP1 – associated encephalopathy. Evaluation of the remainder of the cohort is ongoing with expected completion July 2019. Conclusions: In comparison to our internal data on the diagnostic yield of an epilepsy panel via NGS, this preliminary data suggests that deletion/duplication analysis, while important for complete evaluation of possible genetic etiologies in addition to sequencing, does not result in a high diagnostic yield in this population. Funding: The Goizueta Family Foundation