Genetic Approach to Diagnosis of Intellectual Disability

Intellectual disability is a non-specific phenotype present in a genetically heterogeneous group of disorders. It is characterized by deficits in intellectual and adaptive functioning, presenting before 18 y of age. Identifying the cause of ID is important to provide treatment where available, genetic counseling, recurrence risks and reproductive options for subsequent pregnancies. Advances in technology, especially next generation sequencing and microarrays, have greatly increased the diagnostic yield of evaluation in cases of ID. This paper describes the points in history taking and examination in the evaluation of a proband, and discusses the proper use of newer diagnostic technologies.