Clinical utility of chromosomal microarray analysis in prenatal diagnosis: report of first 6 months in clinical practice

Objective: We studied the clinical utility of chromosomal microarray analysis (CMA) in prenatal diagnosis in a clinical setting in New York City. Methods: Our center began offering CMA to pregnant women undergoing invasive diagnostic procedures for an abnormal structural finding on ultrasound, maternal age of 35 years or older, or elevated risk on aneuploidy screening, beginning March 2012. Our first six months experience is reported. Results: Benign familial variants were the most common finding (16/22 fetuses). Variants of uncertain significance were frequent, especially when fathers were not available for testing (4/22 fetuses). Most patients undertook CMA as part of evaluation of an ultrasound anomaly (52%). One patient terminated a pregnancy based on an ultrasound finding in the setting of a benign familial variant on CMA, and a second terminated a pregnancy based on a copy number variant identified on CMA. Conclusion: For CMA to be maximally useful in prenatal diagnosis, parental DNA samples as well as robust datasets to provide predictive phenotypic information are required. The most common reason for undertaking CMA was to evaluate an ultrasound anomaly, and benign familial variants were a common finding. Genetic services are required to provide pre- and post-test genetic counseling and help families interpret results.