WASHINGTON (HealthDay News) -- French scientists studying four generations of a single family have honed in on two genes associated with fever-related seizures in infants and children.

These "febrile" seizures are the most common seizure disorder in children, affecting 2 percent to 5 percent of children by age 6 in the United States. Most children with the disorder experience seizures only once or a few times and suffer no permanent brain damage. Some children with febrile seizures do develop other seizure disorders, such as epilepsy, later in life.

Of the 51 people in the family, 13 had childhood febrile seizures. In all cases, the seizures stopped by age 7, but six of the 13 developed epilepsy later on. The researchers compared the 13 people affected by febrile seizures to 13 other family members who did not have the attacks.

The study, published in the Neurology, found that those who had febrile seizures shared similarities on chromosome 3 and chromosome 18.

"Identifying the genes responsible for febrile seizures could improve the understanding, treatment and even prevention of this disorder," study author Dr. Rima Nabbout, of the French Institute for Medical Research in Paris, said in a prepared statement.

Previous studies have identified four other chromosome areas associated with febrile seizures.