Most children with microcephaly also have a small brain and mental retardation. However, some children with small heads have normal intelligence. Microcephaly is either caused by exposure to harmful substances during the fetal development, or it may be associated with genetic problems or syndromes that may have a tendency to run in families. Acquired microcephaly may occur after birth due to various brain injuries such as lack of oxygen or infection. Autosomal recessive and autosomal dominant are two patterns in which genes are inherited in a family.
Genes determine our traits, such as eye color and blood type, and can also cause disease.
Autosomal means that both males and females are equally affected. After parents have had one child with autosomal recessive microcephaly, there is a 25 percent chance, or one in four chance, with each pregnancy, to have another child with microcephaly. The following are the most common symptoms of microcephaly. However, each child may experience symptoms differently. The symptoms of microcephaly may resemble other conditions or medical problems.