Anencephaly is a condition that prevents the normal development of the brain and the bones of the skull. This condition results when a structure called the neural tube fails to close during the first few weeks of embryonic development. The neural tube is a layer of cells that ultimately develops into the brain and spinal cord. Because anencephaly is caused by abnormalities of the neural tube, it is classified as a neural tube defect.

Anencephaly is a complex condition that is likely caused by the interaction of multiple genetic and environmental factors. Some of these factors have been identified, but many remain unknown.

Anencephaly is one of the most common types of neural tube defect, affecting about 1 in 1,000 pregnancies. However, most of these pregnancies end in miscarriage, so the prevalence of this condition in newborns is much lower. An estimated 1 in 10,000 infants in the United States is born with anencephaly.

Most cases of anencephaly are sporadic, which means they occur in people with no history of the disorder in their family. A small percentage of cases have been reported to run in families; however, the condition does not have a clear pattern of inheritance. For parents who have had a child with anencephaly, the risk of having another affected child is increased compared with the risk in the general population.

Published Date: October 01, 2019
Published By: National Institutes of Health