Microcephaly

A condition often associated with feeblemindedness.

A condition in which a person has an unusually small head, sometimes caused by the mother having had a rubella infection during pregnancy.

Microcephaly refers to a smaller than normal head circumference with the presumption that the smaller size reflects a smaller-sized brain. Rather than a disorder or disease entity, microcephaly is viewed as a sign of cerebral malformation. Microcephaly does not have a single cause, but rather can result from a number of different factors. Microcephaly can occur as a result of genetics, both in autosomal recessive form and in autosomal dominant form. The autosomal recessive form is more likely to occur if parents are cousins. A third form of genetic transmission of microcephaly is X-linked: The mother is a carrier for the disorder, but only sons are affected. Other genetic causes of microcephaly are directly related to other disorders that result from chromosomal defects. Syndromes that include microcephaly as a marker are continuously being identified.

An abnormally small head, a common birth defect, as from exposure to Accutane.

Congenital abnormality in which the head is abnormally small and the brain is underdeveloped, resulting in some degree of mental retardation (compare macrocephaly); also called microcephalus.

In a newborn, an abnormally small head. Microcephaly is associated with fetal alcohol syndrome, the rare disorder phenylketonuria, Down syndrome, rubella, malnutrition, and exposure to radiation. Once the cause is established, the doctor will help the family determine the appropriate care necessary to help the child develop, because many children born with microcephaly may be develop- mentally delayed.

Abnormal smallness of the head in relation to the size of the rest of the body: a congenital condition in which the brain is not fully developed.

Abnormal smallness of the head, usually associated with learning disability. It may occur as a result of infection of the fetus by, for example, rubella (German measles) or from hypoxic damage to the brain before or during birth.

Abnormal smallness of head (below 1350 cc capacity) often seen in mental retardation.

An unusually undersized head condition. Microcephaly is linked to challenges in learning. It could stem from specific chromosomal irregularities, and it may also emerge if the brain experiences harm before or during birth, or if it sustains injury or illness during early infancy.