Epilepsy affects nearly 3 million Americans. But who is really at risk? Epilepsy can develop in any person at any age. Almost 1% of people will develop epilepsy during their lifetime- that's 60 million people worldwide. In other words, out of 60,000 people filling a big stadium, about 500 have epilepsy. New cases of epilepsy are most common among children, especially during their first year. The rate of new cases gradually declines until about age 10, and then becomes stable. After age 60, the rate starts to increase again. Many famous people in history had or may have had epilepsy, A. including world leaders like Julius Caesar, B. writers like Lewis Caroll, C. artists like Vincent Van Gogh, D. and athletes like Chanda Gunn, goaltender for the U.S. Olympic Hockey team. The causes of epilepsy can be divided into two groups: brain injuries and chemical imbalances in the brain. Anything that injures the brain can lead to seizures, but in over half the cases no cause can be identified. The type of injury that can lead to a seizure is age-dependent. Seizures in children often are caused by birth traumas, infections like meningitis, congenital abnormalities, or high fevers. Seizures in the middle years commonly are caused by head injuries, infections, alcohol, stimulant drugs, or medication side effects. In the elderly, brain tumors and strokes cause a higher proportion of seizures. Not all seizures result from a structural problem in the brain. Chemical imbalances also can cause seizures. Common chemical imbalances that can produce seizures include: Drugs like alcohol, cocaine, and others. Low blood sugar, low oxygen, low blood sodium, or low blood calcium. Kidney failure, liver failure, or other conditions. Doctors will evaluate you for these imbalances by taking a careful history and blood tests. Although these disorders and injuries can explain many cases of epilepsy, often the cause of epilepsy remains "idiopathic," which is the medical term for unknown. Scientists increasingly recognize the importance of genetic factors in the origin of epilepsy. About half the time, no cause for a seizure can be identified. Fortunately, we do not need to know the cause to treat the seizures. Genetics are most relevant to generalized seizures, including absence, generalized tonic-clonic, and myoclonic seizures. Defects in genes don't lead directly to epilepsy, but they can alter the excitability of the brain in a way that predisposes it to seizures. Typically, epilepsy develops because of multiple gene abnormalities, or a gene abnormality in concert with an environmental trigger. Parents with epilepsy worry whether their children will have epilepsy. In most cases, they won't, but they do have a higher risk than others. If the mother has a generalized type of epilepsy, the child's chances of having epilepsy may be as high as 5% to 20%. But if a parent has epilepsy due to a brain injury, the child's chance of having epilepsy is only about 5%. If you or someone close to you is suffering from seizures, please see a physician immediately. "The movies in this series can be viewed in any order. If you wish to watch these clips in their original sequence, the next clip is, "How to Diagnose Epilepsy?"