Internal carotid agenesis

What causes internal carotid agenesis?

The cause of internal carotid agenesis is currently unknown. The malformation is present from birth and is believed to be caused when something happens early during the development of the baby that stops the carotid artery from forming correctly. Most of the time, the malformation is thought to occur by chance. However, less commonly, a person with internal carotid agenesis may also have other diseases or syndromes. People with internal carotid agenesis caused by other syndromes typically have other symptoms or medical problems.

Last updated on 05-01-20

How is internal carotid agenesis diagnosed?

Internal carotid agenesis is diagnosed when one or both of the internal carotid arteries are found to be missing by specific imaging tests. These imaging tests may include angiography, computed tomography scanning (CT scan), and magnetic resonance imaging (MRI). These tests are used to visualize the blood vessels and the surrounding bones. The diagnosis may be confirmed with another imaging test called magnetic resonance angiogram (MRA) that looks specifically at the blood vessels. If people who have internal carotid agenesis do not have symptoms of the malformation, it is typically diagnosed by accident (or incidentally) when evaluating for other health concerns.

Last updated on 05-01-20

Is internal carotid agenesis inherited?

Mutations (changes) in a specific gene have not been associated with internal carotid agenesis, and the malformation is not known to run in families. Therefore, other family members are not known to be at risk to have the malformation. However, if a person with internal carotid agenesis has an aneurysm, other family members may be recommended to have screening to check for aneurysms as well.

Internal carotid agenesis is known to be associated with a few other diseases or syndromes. If an individual has internal carotid agenesis as a sign of another disease or syndrome, then it is possible that the malformation was inherited and that it could be passed on to future generations.

Last updated on 05-01-20

What is the long-term outlook for people affected by internal carotid agenesis?

The long-term outlook for people affected by internal carotid agenesis is typically good. Although the malformation may be associated with complications such as brain aneurysm, there are imaging techniques and surgical procedures that can be used to identify and treat people with aneurysms. People with this malformation may be more likely to experience complications during certain types of surgery, so it is important for a person with internal carotid agenesis to tell all of their doctors, especially surgeons, about the diagnosis. In some cases, internal carotid agenesis may be associated with other diseases or syndromes. In these cases, the long-term outlook may depend on the associated syndrome or disease.

Last updated on 05-01-20

How might internal carotid agenesis be treated?

Internal carotid agenesis may not require any treatment if there are no symptoms. However, since the blood is rerouted through other smaller blood vessels to supply blood to the brain, these blood vessels may develop problems due to the extra blood flow. In some cases, surgery may be an option to relieve symptoms.

Due to the increased risk of aneurysms, many doctors recommend that a person with internal carotid agenesis be screened for the development of aneurysms. However, the condition is rare, it is not clear how often such screening should take place and if screening is actually helpful. If a brain aneurysm is observed, further monitoring or surgery may be necessary.

Last updated on 05-01-20

Name: American Stroke Association National Center 7272 Greenville Avenue
Dallas, TX, 75231, United States
Phone: 888-478-7653 Url:
Name: Brain Aneurysm Foundation 269 Hanover Street
Hanover, MA, 02339, United States
Phone: 888-272-4602 Email: Url:

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The RareGuru disease database is regularly updated using data generously provided by GARD, the United States Genetic and Rare Disease Information Center.

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