There are 4,000 to 5,000 FMF patients in Israel — the largest concentration of the disorder anywhere.

Inheriting the gene from one parent makes the child a symptomless carrier. But if one has the double gene, the disorder is characterized by recurrent and severe attacks of fever, abdominal pains and pains of the joints and the pleura covering the lungs, usually lasting from one to four days.

Untreated, it can cause amyloidosis, in which proteins called amyloids concentrate in the kidneys and cause them to fail, requiring dialysis and shortening life expectancy.

But 25 years ago, a Boston physician, Dr. S.E. Goldfinger, discovered by chance that an anti-gout drug called colchicine cuts the attacks short, but does not eliminate the trigger for them, and failed to help five percent of FMF patients.

In a press conference Sunday, Professor Mordechai Pras of Sheba Hospital declared that he and his colleagues at the U.S. National Institute of Arthritis and Musculoskeletal and Skin Diseases (in Bethesda, Md.) were the first to discover the defective gene, which they dubbed Pyrin (the Greek word for fire). A scientific article describing the discovery was published in the Aug. 22 issue of Cell.

Simultaneously, Professors Eldad Ben-Chetrit and Micha Levy of the internal medicine department at Hadassah-University Hospital in Jerusalem's Ein Kerem, who worked with a French team, claimed to have made the discovery "first."

Although that consortium, which named the defective gene marenostrin ("Our Sea," a Roman phrase for the Mediterranean), had discovered only half the base pairs in the gene, Ben-Chetrit said that "the remaining pairs are not significant and we were first." His team's article is appearing in Nature Genetics.

Ben-Chetrit said that the disease has even affected some Ashkenazi Jews.

"When they married only Ashkenazi Jews, some were carriers but it was very unusual for two carriers to marry. However, when in Israel they began to marry Jews of North African origin, it was more common for offspring to inherit two defective genes," he explained.

Pras declared it will now be possible to conduct a blood test and know for certain whether a person suffers from FMF or is a carrier. Since the symptoms of the disease are not always clear from the outset, colchicine treatment can begin immediately.