Genetic Evaluation of the Child With Intellectual Disability or Global Developmental Delay: Clinical Report

Genetic neurodevelopmental disorders are common in the pediatric population, and establishing a specific diagnosis early provides multiple benefits including prognostication, surveillance for disorder-related complications, accurate recurrence risk, and specific management. This report provides an approach to the genetic evaluation of developmental delay/intellectual disability for the general pediatrician. When possible, genetic testing should be selected by phenotype, and typical distinguishing clinical features to facilitate this are presented. If a specific disorder or group of disorders cannot be ascertained by phenotype, an agnostic (or hypothesis-free) approach is utilized. Recommendations are provided for this agnostic approach based on diagnostic yield and also practical considerations such as test complexity and impact on management. The general guidance in this report for genetic testing does not preclude further evaluation by relevant subspecialists as necessary, including neurologists, developmental pediatricians, and clinical geneticists.