Mental Retardation [Disease/Finding] C4168 Subnormal intellectual functioning which originates during the developmental period. This has multiple potential etiologies, including genetic defects and perinatal insults. Intelligence quotient (IQ) scores are commonly used to determine whether an individual is mentally retarded. IQ scores between 70 and 79 are in the borderline mentally retarded range. Scores below 67 are in the retarded range. (Joynt, Clinical Neurology, 1992, Ch55, p28) 1023334 Mental Retardation M0013414 N0000001995 91138005 Retardation, Mental Disability, Intellectual C0025362 D008607 Mental Retardation Mental Disorders Diagnosed in Childhood [Disease/Finding] Neurobehavioral Manifestations [Disease/Finding]