The impact of chromosomal microarray on clinical management: a retrospective analysis

Purpose: Chromosomal microarray has been widely adopted as the first-tier clinical test for individuals with multiple congenital anomalies, developmental delay, intellectual disability, and autism spectrum disorders. Although chromosomal microarray has been extensively shown to provide a higher diagnostic yield than conventional cytogenetic methods, some health insurers refuse to provide coverage for this test, claiming that it is experimental and does not affect patients' clinical management. Methods: We retrospectively reviewed the electronic medical records of all patients who had abnormal chromosomal microarray findings reported by our laboratory over a 3-year period and quantified the management recommendations made in response to these results. Results: Abnormal chromosomal microarray findings were reported for 12.7% of patients (227/1,780). For patients with clinical follow-up notes available, these results had management implications for 54.5% of patients in the entire abnormal cohort (102/187) and for 42.1% of patients referred for isolated neurodevelopmental disorders (16/38). Recommendations included pharmacological treatment, cancer-related screening or exclusion of screening, contraindications, and referrals for further evaluation. Conclusion: These results empirically demonstrate the clinical utility of chromosomal microarray by providing evidence that management was directly affected for the majority of patients in our cohort with abnormal chromosomal microarray findings.