Evaluation of the Child with Developmental Impairments

PURPOSE OF REVIEW This article discusses the diagnostic evaluation of intellectual developmental disorder, comprising global developmental delay and intellectual disability in children. RECENT FINDINGS With a prevalence of 1% to 3% and substantial comorbidity, high lifetime costs, and emotional burden, intellectual developmental disorder is characterized by limitations in both intellectual functioning (IQ less than 70) and adaptive behavior starting before 18 years of age. Pinpointing the precise genetic cause is important, as it allows for accurate genetic counseling, avoidance of unnecessary testing, prognostication, and tailored management, which, for an increasing number of genetic conditions, targets the pathophysiology and improves outcomes. SUMMARY The etiology of intellectual developmental disorder is heterogeneous, which mandates a structured approach that considers family situation, test costs, yield, and potential therapeutic tractability of the identified condition. Diagnosis of an underlying genetic cause is increasingly important with the advent of new treatments. Still, in many cases, the cause remains unknown, and research is needed to elucidate its complex molecular basis.