Rare polymorphic variants of the AGTR2 gene in boys with non-specific mental retardation

Mental retardation (MR) is a frequent cause of serious handicap in children and young adults. It is defined as an overall intelligence quotient (IQ) lower than 70 associated with functional deficits in adaptive behaviour (such as daily living skills, social skills, and communication), with an onset before 18 years.1,2 Moderate to severe MR (IQ