Skull birth defects are conditions that are present at birth.
These birth defects were created as the fetus was still developing in a pregnant person’s uterus.
Verywell / Danie Drankwalter
What Is Anencephaly?
Verywell / Danie Drankwalter
Approximately 1 in every 4,600 babies in the United States is born with anencephaly.
The neural tube is formed very early in pregnancy.
As it develops and closes, it helps form the brain, skull, spinal cord, and backbone.
If the upper part of the neural tube does not close all the way, anencephaly occurs.
Often, the rest of the brain is not covered by bone or skin.
In most cases, there is no family history of it or other neural tube defects.
In some instances, a familial pattern is suspected.
Some risk factors for anencephaly include:
Anencephaly is more common in girls rather than boys.
Anencephaly is associated with these conditions:
Diagnosis
Anencephaly is often diagnosed before birth.
If it is missed prenatally, it is immediately apparent through appearance when the baby is born.
Most pregnancies with anencephaly end in miscarriage or stillbirth.
Babies who are born with anencephaly will almost always die within a few hours or a few days.
Treatment is supportive and involves helping parents and loved ones say goodbye and grieve their baby.
What Is Craniosynostosis?
A typical babys skull bones have spaces between them called sutures.
They are filled with flexible material.
At around age 2, the sutures become bone and begin to “close” by joining together.
Craniosynostosis comes up whenever one or more of the sutures closes too early.
This premature closure can limit or slow the growth of the babys brain.
The types of craniosynostosis are determined by where the sutures close.
Treatment depends on the severity of the condition.
Treatments for craniosynostosis may include:
What Is Encephalocele?
Encephalocele is a birth defect that happens when the neural tube does not close completely during pregnancy.
The protruding brain is covered in either skin or a thin membrane, creating a “sac.”
Genetics may play a role in causing an encephalocele.
More research is needed into the causes of encephalocele.
Sometimes encephalocele is observed during a prenatal ultrasound.
When this happens, fetal magnetic resonance imaging (MRI) may be ordered.
Summary
Anencephaly, craniosynostosis, and encephalocele are three types of skull birth defects.
They vary in whether they can be detected before birth, at birth, or later.
Anencephaly cannot be treated and is fatal.
Encephalocele usually requires surgery to repair.
Craniosynostosis may require no intervention or need therapy or surgery.
Frequently Asked Questions
There are many types of birth defects that can cause abnormalities in the skull.
Three of the most common are anencephaly, craniosynostosis, and encephalocele.
It is common, affecting about 10% of babies in the U.S.
Centers for Disease Control and Prevention.Anencephaly.
Genetic and Rare Diseases Information Center.Isolated anencephaly/exencephaly.
Golisano Children’s Hospital.Anencephaly.
2018;106:26-30. doi:10.1016/j.ypmed.2017.11.003
Centers for Disease Control and Prevention.Craniosynostosis.
Centers for Disease Control and Prevention.Encephalocele.
Seattle Children’s Hospital.Encephalocele.
Johns Hopkins Medicine.Craniofacial abnormalities.
