Mental retardation:Theconditionof having anIQmeasured as below 70 to 75 and significant delays or lacksinat least two areas of adaptive skills.Mental retardationis present fromchildhood. Between 2 and 3 percent of the general population meet the criteria for mental retardation. Causes of mental retardation include fetal alcohol syndrome and fetalalcoholeffect; brain damage caused by the use ofprescriptionor illegal drugs during pregnancy; brain injury anddisease; andgeneticdisorders, such as Down syndrome and fragile X syndrome. Treatment of mental retardation depends on the underlying cause. In some cases, such as phenylketonuria andcongenital甲状腺功能减退、特殊饮食或药物治疗s can help. In all cases, special education starting as early in infancy as possible can help people with mental retardation maximize their abilities.
