Scientists Discover New Epilepsy Gene
It is a boon to the genetical students and epileptic patients that Harvard Medical School found a new gene causes epilepsy.
Here the report goes, "Boston--Harvard Medical School affiliate Beth Israel Deaconess Medical Center--Scientists studying the genetic basis of epilepsy have discovered a gene that is not only required for proper brain development, but which also may play an important role in vascular disease and stroke. Researchers at Boston's Beth Israel Deaconess Medical Center for the first time have found that the gene filamin 1 (Flnl), which has previously been implicated in platelet function and cell motility outside the central nervous system, plays a critical role in human brain development and causes epilepsy when its normal function is disrupted. They also report that patients with F1n1 mutations are prone to suffering strokes and often are born with a serious vascular anomaly called patent ductus arteriosus. Their findings are the cover story of the December Neuron. "No one realized until now that this gene played a role in the brain" says Christopher A. Walsh, MD, PhD, director of the neurogenetics laboratory at Beth Israel Deaconess Medical Center, and principal investigator of the Neuron study, "Mutations in Filamin 1 Prevent Migration of Cerebral Cortical Neurons in Human Periventricular Heterotopia." "We are, of course excited about the role this gene is playing in the developing brain, but we are also interested in F1n1's connections to stroke and vascular development," continues Walsh. Periventricular heterotopia (PH) is a disorder in which neurons in the brain fail to migrate to their proper location during development, and which results in epilepsy in affected females. Mutations in F1n1 cause this disorder in females, while males with F1n1 mutations die before birth, presumably due to an essential role F1n1 has in the development of the embryo. Walsh and colleagues first homed in on the gene for PH by studying families in which the disorder is inherited. Using gene mapping techniques they narrowed down their search from a possible 60,000 genes to approximately 100 genes. They then studied about a dozen of these genes to determine if any were mutated in their PH patients. Walsh estimates that he and his team spent about six person-years mapping and testing genes before mutations in F1n1 were identified. This gene-hunt has been a full time job for the past three and a half years for the first author of the Neuron paper, Jeremy Fox. "This kind of work is very unpredictable. What pays off in the end is persistence," comments Fox. Walsh speculates that F1n1 acts as an engine that initiates cell migration from deep within the brain to the area where development of the cortex takes place. With some of this migration blocked by F1n1 mutations, many neurons remain deep within the brain and possibly cause epilepsy by making inappropriate connections. Patients with PH mutations also often suffer from strokes and vasculature defects, and Walsh believes that more subtle F1n1 mutations may be found in many people with these other problems. His group plans to collaborate with colleagues at Harvard Medical School to study the non-neuronal roles of F1n1, while continuing studies into the precise role of F1n1 in migrating neurons in the developing brain.
Contributed by dipjyoti. Posted on March 5, 2007.
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