French Locate Seizure Gene
French scientists have identified a gene associated with the kind of brain seizure that killed Olympic sprinter Florence Griffith Joyner.
Faulty copies of the gene, known as CCM1, are responsible for the development of tangled blood vessels in the brain known as cavernous angiomas, according to a study by three laboratories in Paris.
The abnormality is found in one in every 40 Americans, and the condition is inherited in half of the cases.
In most cases, these tangles remain quite small for many years, making them hard to find even with sophisticated imaging equipment and risky to remove. Eventually, the tangles swell and engulf more of the brain. Without surgery, they trigger seizures, paralysis and potentially fatal strokes, often with little warning.
Researchers said understanding CCM1 may lead to early testing and treatments for cavernous angiomas.
``Often, the first clinical sign of the disease is a stroke or death,″ said geneticist Doug Marchuk of Duke University, a member of an American research team that has also linked CCM1 with the brain lesions and will release its study next month. ``A DNA test should be readily available. If you know who is at risk, you can aggressively treat them early.″
An autopsy showed that Ms. Griffith Joyner died in her sleep a year ago at 38 from a seizure triggered as a result of cavernous angioma. The Olympic gold medalist had a history of seizures in the 1990s.
But it is unknown whether she had, in fact, a bad copy of the CCM1 gene and suffered from the inherited form of the brain lesions
On June 13, Houston Astros manager Larry Dierker suffered a violent seizure during a baseball game. Surgeons removed a cavernous angioma, and he returned to the dugout a month later.
In the French study, researcher Elisabeth Tournier-Lasserve and others examined unrelated patients from 20 families with histories of cavernous angiomas, including a high frequency of multiple lesions. CCM1 mutations were found in 12 of the patients. The results appear in the October issue of the journal Nature Genetics.
In the U.S. study, 16 of 21 Mexican-American families were found to share the mutation. Their report will be published in the November issue of Human Molecular Genetics.
``Until now, little has been known about the molecular mechanisms leading to these lesions,″ said geneticist Mikka Vikkula of Catholic University in Belgium. ``Identifying the causative gene and the kinds of mutations it contains allows us to start thinking of completely new ways of treating the disorder.″
Neither study answered several lingering questions about CCM1, including whether the gene is implicated in non-inherited forms of the disease.