Anencephaly: Symptoms & Signs

Medically Reviewed on 10/23/2021

Anencephaly is a type of neural tube defect, a birth defect in which there is an absence of the forebrain, the largest part of the brain consisting mainly of the cerebrum, which is responsible for thinking and coordination. The remaining brain tissue is usually exposed and is not covered by bone or skin.

Signs and symptoms include an absence of the bony covering over the back of the head and missing bones along the front and sides of the head. Infants born with anencephaly are usually blind, deaf, and never attain consciousness. Affected infants may die shortly after birth or within days of birth. Affected individuals do not survive infancy.

Cause of Anencephaly

The exact cause of anencephaly is not known.

Other anencephaly symptoms and signs

  • Absence of All or Part of the Brain
  • Absence of the Bony Covering Over the Back of the Head
  • Blindness
  • Deafness
  • Missing Bones Along the Front and Sides of the Head


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Jameson, J. Larry, et al. Harrison's Principles of Internal Medicine, 20th Ed. New York: McGraw-Hill Education, 2018.