Etiology and Pathophysiology of Childhood Mental Retardation

Etiology and Pathophysiology of Mental Retardation

General Considerations

Intellectual abilities depend to a great degree on the integrity of the CNS. A variety of biomedical causes can disrupt this integ-rity and start the process leading to mental retardation. It should be kept in mind, however, that the term mental retardation de-scribes the overall level of functioning, encompassing current in-tellectual and adaptive skills. These, in turn, are shaped by other factors besides CNS integrity, such as the patient’s general state of health and associated disabilities, environmental factors (such as nurturing, learning opportunities, supports) and psychologi-cal factors (such as the person’s self-image, psychopathological characteristics, motivation). Thus, a biomedical cause, whether genetic or acquired, may be a primary cause that will start the process of developmental delay but will not necessarily be the only factor responsible for the functional outcome, which will depend on the synergistic or cumulative effects of all factors in-volved. It is important to know as much as possible about the “primary” cause for a number of reasons:

Treatment possibilities can include early institution of diet in phenylketonuria (PKU) and thyroid hormone supplementation in congenital hypothyroidism. Primary prevention of the recurrence of the same condition using, for example, parental education to pre-vent fetal alcohol syndrome and enable genetic counseling for the family. Early recognition and treatment of complications known to be associated with the particular mental retardation syndrome, such as hypothyroidism in Down syndrome. Research on causation and prevention Assessment of epidemiology, which is important in public policy (planning for services) as well as in prevention Un-derstanding of prognosis in association with a particular disorder Support for the family and other caregivers by dispelling miscon-ceptions and anxieties related to uncertainty about the cause

·           Treatment possibilities, which can include early institution of diet in phenylketonuria (PKU) and thyroid hormone supple-mentation in congenital hypothyroidism.

·           Prevention, such as primary prevention of the recurrence of the same condition using, for example, parental education to prevent fetal alcohol syndrome and enabling genetic coun-seling for the family.

·           Early recognition and treatment of complications known to be associated with the particular mental retardation syndrome, such as hypothyroidism in Down syndrome.

·           Research on causation and prevention.

·           Assessment of epidemiology, which is important in public policy (planning for services) as well as in prevention.

·           Understanding of prognosis in association with a particular disorder.

·           Support for the family and other caregivers by dispelling miscon-ceptions and anxieties related to uncertainty about the cause.