Ref2242ed to as mental retardation or cognitive impairment as well.
Affects approximately 0.5% of the population.
Clinical diagnosis based on IQ of less than 50 and limitations in activities of daily living.
In childhood diagnosis based on developmental delays such as motor, cognitive or speech delays.
Most severe forms of intellectual disability have a genetic cause.
55-60% of patients with severe intellectual disability have no apparent cause.
De novo point mutations can be a major cause of severe intellectual disability.
Estimated more than 1000 genes mutations may cause intellectual disability.