Introduction: Genetic abnormalities including common aneuploidies and copy number variants are known to influence both parental decisions regarding pregnancy and outcomes for infants with structural anomalies. Current guidelines now recommend chromosomal microarray (CMA) testing in pregnant patients undergoing invasive prenatal diagnosis when a fetus with a major structural anomaly is identified in order to detect copy number variants in euploid fetuses. However, in patients with a normal karyotype, the utility of CMA in predicting prognosis specifically for prenatally diagnosed congenital heart disease (CHD) is unknown.
Methods: This was a University of California Fetal Consortium retrospective cohort study of all cases of prenatally diagnosed CHD that completed either a prenatal or postnatal CMA between 2009 and 2016. Chart review was performed to determine maternal characteristics, ultrasound findings, genetic testing results, and perinatal (prenatal, delivery, and neonatal) course for each case. Neonatal outcomes were compared between cases with normal and abnormal CMA results.
Results: We identified 261 cases of prenatally diagnosed CHD among 5 participating institutions. Of these, 48 with aneuploidy were not further analyzed. Of the remaining 213 cases, 100 had either a prenatal or postnatal CMA completed and, of these, 19 were abnormal (2 likely pathogenic, 17 variants of uncertain significance). CHD cases with abnormal CMA results had a lower 30-day survival (73.7% vs. 91.8%, P = 0.03) and longer hospital stay (63.6 d vs. 55.4 d, P = 0.004) than those with normal CMA results.
Conclusion: The prevalence of CMA abnormalities was high in this cohort. CMA abnormalities not detectable on routine karyotype were associated with worse outcomes in infants with CHD. CMA should be performed routinely when CHD is diagnosed.