Cerebral cavernous malformation
Cerebral cavernous malformations are clusters of enlarged, irregular blood vessels in the brain or spinal cord that can cause neurological symptoms or bleeding.
Overview
Cerebral cavernous malformations are collections of small blood vessels (capillaries) that are enlarged and irregular in structure. These capillaries have abnormally thin walls and lack support tissues, such as elastic fibers, making them prone to leakage. While these malformations can occur anywhere in the body, they typically produce serious symptoms only when located in the brain or spinal cord.
Approximately 25 percent of individuals with this condition never experience health problems. Others may experience:
- Headaches
- Seizures
- Paralysis
- Hearing or vision loss
- Bleeding in the brain (cerebral hemorrhage), which can be fatal
The severity of the disorder depends on the location and number of malformations, which can change in size and number over time.
Types
- Familial form: Passed from parent to child; affected individuals typically have multiple malformations.
- Sporadic form: Occurs in people with no family history; these individuals typically have only one malformation.
Causes
Familial cerebral cavernous malformations are caused by mutations in three genes: KRIT1 (also known as CCM1), CCM2, and PDCD10 (also known as CCM3). These genes produce proteins that strengthen the junctions between blood vessel cells, limiting leakage. Mutations impair this complex, leading to weakened junctions.
These three genes account for 85 to 95 percent of familial cases. The cause of the sporadic form is currently unknown.
Inheritance
This condition is inherited in an autosomal dominant pattern, meaning one copy of the altered gene in each cell is sufficient to cause the disorder. In familial cases, the mutation is inherited from an affected parent.