Anencephaly is a birth defect in which part of the brain and the skull are not fully developed.
If you baby is born with anencephaly, it means part of their brain and the skull that surrounds the brain are not fully formed. Anencephaly is a neural tube defect (brain or spinal cord) that affects your baby early during pregnancy.
In most cases of anencephaly, all or part of the brain that enables vision, hearing, thinking and movement — called the cerebrum — is missing. In addition, the skull bones that cover the back of the head are missing. Sometimes, skull bones on the side and front of the head may also be absent.
Anencephaly is caused by a type of neural tube defect that happens during pregnancy. Neural tube defects happen during the formation of the brain and spine. During normal development, cells that will eventually become the brain and spine start out flat and roll into a tube, called the neural tube. When the neural tube does not close completely, the opening that is left is called a neural tube defect.
Your child may be at risk for a neural tube defect and anencephaly if you had a previous child with a neural tube defect. Neural tube defects can be caused by an inherited genetic defect and/or environmental factors.
Often, anencephalic pregnancies end in miscarriage or still birth. A child born with anencephaly may have the following symptoms: