Detection rate of chromosomal microarray genetic testing in patients with cerebral palsy (P4.152)

Objective: To assess the detection rate of chromosomal microarray (CMA) when utilized in patients with cerebral palsy (CP). Background: Several medical organizations, including the AAN[1], support the use of CMA in patients with neurodevelopmental disabilities such as intellectual disability (ID), developmental delay (DD), autism spectrum disorder (ASD), and multiple congenital anomalies (MCA). The AAN has also issued a practice parameter regarding the diagnostic assessment of patients with CP[2]. This parameter includes recommendations for neuroimaging, but states that metabolic/genetic causes that underlie or masquerade as CP are infrequent (less than 4%). This parameter was issued in 2004, prior to the onset of high-resolution CMA. Design/Methods: We retrospectively assessed our clinical laboratory database for patients with CP who underwent high-resolution CMA from September 1, 2010 through September 30, 2016. Testing indication (ICD-9/ICD-10 codes) included CP with or without additional features. Results: There were 69 out of 11,370 patients with CP (0.6%) in our database. Among those with CP, 48 had a normal result (69.6%), 12 had a variant of unknown significance (VOUS) result (17.4%), and 9 had a pathogenic result (13.0%). Two patients with pathogenic copy number variants (CNVs) had a 17p12 duplication consistent with Charcot-Marie-Tooth type 1A. Conclusions: The rate of patients with CP in our testing database is low (0.6% of total referrals), indicating that clinicians do not consider genetic conditions a common underlying etiology. However, the rate of pathogenic CNVs in this cohort (13%) is comparable to and in some cases higher than pathogenic detection rates reported in individuals with ID and other guideline-recommended indications for CMA. High-resolution CMA should be a recommendation for diagnostic testing in patients with CP. Study Supported by: Disclosure: Dr. Vanzo has received personal compensation for activities with Lineagen as an employee. Dr. Vanzo has stock and/or stock options with Lineagan. Dr. Vanzo has received research support from Lineagan. Dr. Harward has received personal compensation for activities with Lineagen. Dr. Harward holds stock and/or stock options in Lineagen, which sponsored research in which Dr. Harward was involoved as an investigator. Dr. Harward holds stock and/or stock options in Lineagen. Dr. Harward has received research support from Lineagen. Dr. Ho has received personal compensation for activities with Lineagen as an employee. Dr. Ho holds stock and/or stock options in Lineagen, an employee. Dr. Ho has received research support from Lineagen. Dr. Wassman has received personal compensation for activities with Lineagen as an employee. Dr. Wassman holds stock and/or stock options in Lineagen.