It can happen. an automobile or other type of accident involving a sudden impact to the embryo while the mother is pregnant. It is also entirely possible for accidents- including accidents of war and crime ( getting hit with bits of bomb fragments from terrorist action) could cause something that one might be tempted to call mental retardation. I know of a case where a very sick man beat up another man ( over some moronic-no pun intended) cause such as a parking space, with some heavy tool. The victim survived but to this day- ( he's retarded) accidents and crimes can do this, as for example one could lose one's voice by exposure to toxic fumes from a chemical explosion ( don;t hit oil trucks) with no external signs of trauma or ( battle damage). The motto of the wise is- Beware of surprises- and these are downright negative ones. Amnesia can be triggered by accident, war action or terrorist crime... as the girl from the U S S R,, it happens.
In 4% of bacterial meningitis cases in children, there is seen to be some mental retardation.
Exposure to lead can also cause mental retardation.
Overstudy does not cause mental retardation.
In about 35% of cases, the cause of mental retardation cannot be found.
The two conditions are not at all related. Autism does not cause mental retardation.
Hyperthyroidism, whooping cough, chickenpox, measles, and Hib disease (a bacterial infection) may cause mental retardation if they are not treated adequately.
Maternal infections and such illnesses as glandular disorders, rubella, toxoplasmosis, and cytomegalovirus (CMV) infection may cause mental retardation
Mental retardation may be caused by an inherited abnormality of the genes, such as fragile X syndrome.
An infection of the membrane covering the brain (meningitis) or an inflammation of the brain itself (encephalitis) cause swelling that in turn may cause brain damage and mental retardation.
The treatment team will depend on the underlying cause of mental retardation. A neurologist, neuropsychologist, child psychiatrist, and/or development pediatrician may be helpful for nearly all cases of mental retardation
Symptoms of mental retardation may appear at birth or later in childhood. Time of onset depends on the suspected cause of the disability.
Fragile X, a defect in the chromosome that determines sex, is the most common inherited cause of mental retardation.