Epilepsy affects about 2.4 million Americans. Roughly 70 percent of cases are idiopathic, although a genetic basis is strongly suspected in most of them.
The Epilepsy Phenome/Genome Project (EPGP), one of the largest epilepsy research studies ever attempted, seeks to understand the pathophysiology and clinical expression of idiopathic epileptic syndromes. All three Mayo Clinic campuses are among the 29 centers participating in this international study, which is funded by the National Institutes of Health through the National Institute of Neurological Disorders and Stroke.
The study involves collecting detailed phenotypic information from patients with idiopathic or genetically based epilepsy. State-of-the-art bioinformatics will then be used to identify the potential contribution of genomic and somatic variability to the epilepsy phenotype, developmental anomalies of the central nervous system, and the varied therapeutic responses of patients treated with anti-epilepsy medications.
About 4,200 patients are enrolled in the study, including 320 at Mayo Clinic in Rochester, Minn. Although some of them were Mayo patients, many others were sent by physicians throughout the U.S. who learned about the study. "We have finished the patient enrollment and are now gathering information and doing the analysis," says Gregory D. Cascino, M.D., a neurologist who is the primary EPGP investigator at Mayo in Minnesota. "We're already beginning to analyze patterns, but the process may take several years."
Two types of patients were enrolled in the study:
In addition to providing blood samples, all study participants are undergoing EEG, MRI and diagnostic interviews. Patients' medical records from Mayo or other centers also are being reviewed. "The purpose of the study is to identify genes involved in genetically determined epilepsies, to help with diagnosis and to understand the clinical manifestations," Dr. Cascino says.
The researchers also hope to discover if certain genetic factors may indicate that a patient's epilepsy is more likely to be medically refractory. This type of genetic information is important to family members after a diagnosis of epilepsy. "Families are interested in knowing not only about treatment options, but also the possible cause of epilepsy," Dr. Cascino says. "They want to understand the likelihood of developing seizures themselves or of passing a seizure disorder on to their offspring."
Mayo Clinic in Minnesota is also participating in the Human Epilepsy Project, a planned multicenter, prospective study of patients with newly diagnosed focal epilepsy. Although enrollment hasn't yet begun, participants in this study:
The study's primary goal is to identify clinical characteristics and biomarkers predictive of disease outcome and progression, as well as treatment response.
"We hope to learn what we can about the prognosis for these newly diagnosed patients, as well as which anti-epilepsy medications are effective and which cause side effects," Dr. Cascino says. "This is a very exciting project because the number of new epilepsy diagnoses in the United States is conservatively estimated at 200,000 a year, and very little is known about prognostic factors."
This participation in international, multicenter research studies is possible because Mayo has extensive experience with epilepsy as well as the resources to conduct EEG and MRI according to highly specific research protocols. Notes Dr. Cascino: "As a major comprehensive epilepsy program, Mayo is available not only for patient care but also for cutting-edge research."