Diagnostic approach for genetic causes of intellectual disability.

Abstract

Intellectual disability (ID) is the most common disability among people under the age of 20 years. In the absence of obvious non-genetic causes of ID, the majority of cases of severe ID are thought to have a genetic cause. The advent of technologies such as array comparative genomic hybridization, single nucleotide polymorphism genotyping arrays, and massively parallel sequencing has shown that de novo copy number variations and single nucleotide variations affecting coding regions are major causes of severe ID. This article reviews the genetic causes of ID along with diagnostic approaches for this disability.