A Decade’s Experience in Pediatric Chromosomal Microarray Reveals Distinct Characteristics Across Ordering Specialties

Chromosomal microarray (CMA) is a testing modality frequently used in pediatric patients, however previously published data on its utilization is limited to the genetic setting. Here, we performed a database search for all CMA testing performed from 2010 to 2020, and delineate the diagnostic yield based on patient characteristics, including sex, age, clinical specialty of providers, indication of testing, and pathogenic finding. The indications for testing were further categorized into Human Phenotype Ontology (HPO) categories for analysis. This study included a cohort of 14,541 patients from 29 different medical specialties, of which 30% were from the genetics clinic. The clinical indications for testing suggested that neonatology patients demonstrated the greatest involvement of multi-organ systems, involving the most HPO categories, compared to developmental behavioral pediatrics and neurology patients being the least. The top pathogenic findings for each specialty differed, likely due to the varying clinical features and indications for testing. Deletions involving the 22q11.21 locus were the top pathogenic findings for patients presenting to genetics, neonatology, cardiology, and surgery. Our data represents the largest pediatric cohort published to date. This study is the first to demonstrate the diagnostic utility of this assay for patients seen in the setting of different specialties, and provides normative data of CMA results among a general pediatric population referred for testing due to variable clinical presentations.