This seems to occur more frequently in Hispanic people. Even in families where development of a cavernous malformation seems hereditary, it is unclear which members of the family are likely to inherit this predisposition or whether they will ever become symptomatic and require treatment. The gene responsible for familial cavernous malformations is located on chromosome number 7. Cavernous malformations, for the most part, are thought to be acquired. This means that people are not born with them, that the malformations develop some time during life.
Cavernous malformations are extremely rare in children.
Cavernous malformations have been observed to develop after radiation therapy in both children and adults and following surgical biopsy for other brain lesions. One theory is that cavernous malformations develop from an abnormal response of the brain to a small hemorrhage, like from a capillary telangiectasia. The brain may develop new blood vessels as a response to a hemorrhage in order to try to repair the brain and remove the old blood, but the new vessels also are very fragile, with a tendency to rupture. This results in further small bleeding episodes and more growth of new vessels, and so on. This is usually a slow process and may account for the slow growth of these malformations over many years.