The American Academy of Pediatrics Committee on Genetics present a recommended clinical genetics diagnostic approach to the evaluation of intellectual disability or global developmental delays. The report addresses the advances in diagnosis and treatment of children with intellectual disabilities since the original AAP report in 2006 . Intellectual disability (ID) is characterized by significant limitations both in intellectual functioning and in adaptive behavior as expressed in conceptual, social and practical adaptive skills. The disability originates before age 18 years, and the prevalence is estimated at 1% to 3%. Global development delay (GDD) is defined as a significant delay in 2 or more developmental domains, including gross or fine motor, speech/language, cognitive, social/personal, and activities of daily living, and is thought to predict a future diagnosis of ID. GDD is applied to younger children < 5 years, and the prevalence is 1% to 3%, similar to that of ID. The term ID is applied to older children for whom IQ testing is valid and reliable.
In patients with GDD or ID, chromosome microarray and fragile X are first line diagnostic tests. MRI remains important in some patients. The use of whole-exome sequencing as a diagnostic test is gaining popularity. 
COMMENTARY. The benefits of a comprehensive evaluation were studied in 20 families of children with ID, with and without an etiologic diagnosis . A diagnosis was thought to help guide expectations and management and provide hope for treatment. Diagnosis assisted families in obtaining desired services, especially in schools. Families differed in their “need to know” a specific diagnosis, ranging from strong to indifferent. Families varied in their emotions and actions regarding prenatal genetic diagnosis. The importance of the pediatrician and clinical geneticist discussion is stressed before deciding on the best approach to the diagnostic evaluation. The pediatric neurologist has an equally important role in the arrival at the correct etiological diagnosis and management of a child with GDD or ID.