A 5-year-old child is notably showing deficits in key areas of development that include social interaction, communication, and behavior. Up to 2 years of age he appeared to be developing well, but then he began to show abnormal patterns of behavior (e.g., repetitive hand-flapping) and started to lose language skills.
His physical examination was unremarkable with no observable acute neurologic pathology appreciated. An extensive workup was undertaken and included metabolic studies, neuroimaging, fragile X testing, and electroencephalography--all of which were negative.
He does not appear to fit any specific syndrome. However, concern had arisen for an autism spectrum disorder based on symptom criteria delineated in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition.
His parents are now planning on having another child and are concerned that an underlying genetic condition may have resulted in a diagnosis of autism spectrum disorder.
What should be the next test ordered to diagnose possible chromosomal abnormalities in this child?
This question appears in Med-Challenger Pediatric Medicine Review with CME
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