Worldwide, approximately 70 million people suffer from idiopathic epilepsy, an epileptic illness which doesn't have any apparent cause.

In Heinrich Hoffmann's classic children's story "Slovenly Peter", Johnny Look-in-the-Air whose "eyes were still astray /Up on high /in the sky" until he fell down "Bump! Thump!" could well have suffered from that kind of epilepsy.

"This form of epilepsy usually affects children at the age of four or five," Dr. Armin Heils, a physician in Bonn, explained. "The children become unconscious for ten or twenty seconds, turn their eyes upwards, but continue to walk or run - until they stumble and fall."

The symptoms can be very different, ranging from unconsciousness lasting several seconds and convulsions of the arms or legs to severe spasms. Some teenagers also develop dangerous generalized seizures with unconsciousness, severe muscular cramps and frothing at the mouth.

Scientists in the National Genome Research Network are searching for the causes of this illness. Recently Dr. Heils and his colleagues have discovered a defect gene which can trigger epilepsy.

The genetic material of 46 families in which this form of epilepsy frequently occured helped Dr. Armin Heils and his team to track down a gene that plays a decisive role in the development of the disease.

Page 3: why a defective ion channel triggers the epileptic seizure.