Intellectual Disability Exome

Intellectual disability (ID) is a neurodevelopmental disorder characterized by significant limitations in intellectual functioning (i.e., IQ below 75), limitations in adaptive behavior which comprises three skills types (conceptual skills, social skills and practical skills), and typically presents in infancy or early childhood. ID may be observed as part of a syndrome with other phenotypic findings or may be an isolated finding without accompanying additional physical, neurological, and/or metabolic abnormalities (non-syndromic). Severity of ID is highly variable and is estimated to affect approximately 1% to 3% of the population. Intellectual disability can be a result of genetic as well as environmental factors. Environmental factors may involve malnutrition/undernutrition, exposure to toxic substances, physical trauma or head injury, severe infection, pregnancy complications, and childhood illness. Genetic causes explain about 50% of cases and may involve chromosomal abnormalities or monogenic defects. There are now over 1000 genes that have been reported to be associated with either X-linked, autosomal-dominant, or autosomal-recessive forms of non-syndromic and syndromic ID. Determining the molecular basis of intellectual disability can help determine the recurrence risk and anticipate disease course. The intellectual disability exome involves analysis of exome sequencing data in a predefined yet regularly updated set of genes associated with non-syndromic and syndromic forms of intellectual disability.