What causes intellectual disability? Can it be prevented?
Intellectual disability can start anytime before a child reaches the age of 18 years. It can be caused by injury, disease, or a brain abnormality. These causes can happen before a child is born or during childhood. For many children, the cause of their intellectual disability is not known. Some of the most common known causes of intellectual disability are Down syndrome, fetal alcohol syndrome, and fragile X syndrome, all of which occur before birth. Other causes that take place before a child is born include genetic conditions (such as Cri-du-chat syndrome or Prader-Willi syndrome), infections (such as congenital cytomegalovirus), or birth defects that affect the brain (such as hydrocephalus or cortical atrophy). Other causes of intellectual disability (such as asphyxia) happen while a baby is being born or soon after birth. Still other causes of intellectual disability do not happen until a child is older. These may include serious head injury, stroke, or certain infections such as m
