title: Comprehensive evaluation of the child with intellectual disability or global developmental delays.
abstract: Global developmental delay and intellectual disability are relatively common pediatric conditions. This report describes the recommended clinical genetics diagnostic approach. The report is based on a review of published reports, most consisting of medium to large case series of diagnostic tests used, and the proportion of those that led to a diagnosis in such patients. Chromosome microarray is designated as a first-line test and replaces the standard karyotype and fluorescent in situ hybridization subtelomere tests for the child with intellectual disability of unknown etiology. Fragile X testing remains an important first-line test. The importance of considering testing for inborn errors of metabolism in this population is supported by a recent systematic review of the literature and several case series recently published. The role of brain MRI remains important in certain patients. There is also a discussion of the emerging literature on the use of whole-exome sequencing as a diagnostic test in this population. Finally, the importance of intentional comanagement among families, the medical home, and the clinical genetics specialty clinic is discussed.
authors.forename: John B
authors.initials: JB
authors.lastname: Moeschler
authors.forename: Michael
authors.initials: M
authors.lastname: Shevell
mesh_terms: D002658:Developmental Disabilities / Q000175:diagnosis* / Q000235:genetics / Q000523:psychology; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000175:diagnosis* / Q000235:genetics / Q000523:psychology; D007621:Karyotyping / Q000379:methods; D008297:Male