55. CMA and concurrent karyotyping for MCA, ASD, and/or DD/ID patients: Cost effectiveness based on our 7-year experience

Abstract

Chromosomal microarray (CMA) as first-tier testing to detect copy number variants (CNVs) and loss of heterozygosity (LOH) in patients with multiple congenital anomalies (MCA), autism spectrum disorder (ASD), developmental delay (DD), and/or intellectual disability (ID) has replaced other forms of testing such as chromosome analysis. However, chromosome analysis will complement CMA if balanced genomic abnormalities are of concern. Consideration of cost effectiveness and impact on clinical management for concurrent testing has not been well studied, and there is no consensus on how best to utilize testing strategies. To attempt to assess, 3,360 postnatal cases were reviewed in patients with MCA, ASD, DD and/or ID. An incremental cost effectiveness ratio (ICER) of combined testing demonstrated the cost of each informative chromosome finding was significantly higher for patients with clinically insignificant CMA findings versus clinically significant CMA results. Chromosome analysis alone achieved laboratory diagnosis in two patients (0.06%) and contributed additional information to CMA results in 199 (5.92%) cases. Most abnormal chromosome results were related to counseling for reproductive and recurrence risk assessment, while a few cases led to changes in laboratory testing and specialist referral. Overall, results suggest that a stepwise approach of CMA testing with reflex to chromosome analysis on appropriate cases with clinically significant CMA findings may be a more cost-effective testing algorithm for patients with MCA, ASD, and/or DD/ID. This algorithm may also be useful in the context of other testing modalities currently being adopted such as such as WES for these patients.