Testing for Genetic Syndromes Related to Developmental Delay (DD), Intellectual Disability (ID), and Autism Spectrum Disorder (ASD)

Developmental delay (DD) is defined as any significant lag in a child's physical, cognitive, emotional, or social maturity when compared to established norms. Intellectual disability (ID) is classified by neurocognitive impairments as well as significant limitations in adaptive living skills. Autism spectrum disorders (ASDs) represent a neurodevelopmental continuum with varying degrees of social impairment. Laboratory testing should be considered as part of a comprehensive evaluation for individuals with ASD and/or DD/ID (with or without comorbidities) to assist with decisions about treatment and management. An initial workup should include chromosomal microarray (CMA), which offers the highest estimated diagnostic yield in individuals with unexplained DD/ID, ASD, and multiple congenital anomalies (MCAs). CMA is preferred to karyotyping as a first-tier test. Screening for fragile X syndrome and, in some situations, metabolic testing, is also recommended.