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Internal carotid agenesis

Other Names for this Disease
  • Agenesis of the internal carotid artery
  • Internal carotid artery agenesis
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Internal carotid agenesis occurs when one of the blood vessels which supply blood to the brain does not develop (agenesis).  It is rare, occurring in less than 0.01% of people.[1]  Usually there is a pair of internal carotid arteries, one on the left side and one on the right side; agenesis occurs on the left side three times more frequently than on the right side.[2]  Individuals with this condition may not have any symptoms because there are several blood vessels transporting blood to the brain such that if one does not develop, the others can function in its place.  However, if symptoms occur, they may include headache, blurred vision, paralysis of some of the nerves in the head (palsy), epilepsy, or muscle weakness on one side of the body (hemiparesis).[2]  The main concern with internal carotid agenesis is the increased risk for enlargement of the other blood vessels (aneurysm), which can occur in up to 67% of people with this condition (compared to 2-4% of individuals without this condition).[3]
Last updated: 3/17/2011


  1. Afifi, AK, Goersky JC, Menezes A, Smoker WR, Bell WE, and Jacoby CG. Cerebral Hemiatrophy, Hypoplasia of Internal Carotid Artery, and Intracranial Aneurysm: A Rare Association Occuring in an Infant. Arch Neurol. 1987; 44:232-235. Accessed 3/14/2011.
  2. Florio F, Balzano S, Nardella M, Strizzi V, Cammisa M, Bozzini V, Catapano G, and D'Angelo V. Congenital Absence of the Internal Carotid Artery. Vardiovasc Intervent Radiol. 1999; 22:74-78. Accessed 3/14/2011.
  3. Lee JH, Oh CW, Lee SH, and Han DH. Aplasia of the internal carotid artery. Acta Neruochin. 2003; 145:117-125. Accessed 3/14/2011.
  4. Claros P, Bandos R, GIlea I, Claros Jr A, Capdevila A, Gardia Rodrigues J, Claros A. Major congenital anomalies of the internal carotid artery: agenesis, aplasia and hypoplasia. Int J Pediatr Otorhinolaryngol. 1999; 49:69-76. Accessed 3/14/2011.
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