For release: Thursday, August 30, 1990
Scientists at the National Institute of Neurological Disorders and Stroke (NINDS) have linked three outbreaks of Creutzfeldt-Jakob disease (CJD) in Europe and Israel to a genetic mutation found in the outbreaks' victims.
CJD is a rare, rapidly progressive dementia with a worldwide yearly incidence of one per million. The disease afflicts about 300 Americans annually, and kills within one year after symptoms of mental deterioration and involuntary movements appear.
"This is the first significant mutation to be described in CJD," said Paul Brown, M.D., one of the scientists who contributed to the discovery. The work was conducted by investigators at the NINDS Laboratory of Central Nervous System Studies in conjunction with colleagues in Czechoslovakia and Israel. The findings appear in the July 21, August 25, and September 8 editions of the British journal The Lancet .
Since 1975, CJD has affected 22 people in Orava, a rural region in Czechoslovakia with only 15,000 residents. This incidence of CJD is hundreds of times higher than the normal rate. Furthermore, the outbreak is continuing, according to D. Carleton Gajdusek, M.D., a Nobel prize winner and chief of the NINDS laboratory.
"This problem has all the indications of escalating into a major international scientific concern," according to Dr. Gajdusek. Part of this scientific interest focuses on the similarities between CJD and another, better-known dementia--Alzheimer's disease.
CJD has long interested scientists studying Alzheimer's disease. In addition to sharing basic symptoms, both Alzheimer's disease and CJD are amyloidoses--diseases in which the brain develops plaques of an abnormal protein called amyloid. While different proteins create the amyloid found in the two diseases, Dr. Brown said, "the same basic mechanism may be going on in the brain in Alzheimer's disease and CJD."
The mutation detected by Dr. Gajdusek and his colleagues was found on a gene that has been linked to amyloid plaques. The gene is located on chromosome 20 and is called the scrapie amyloid precursor gene. Thus far, the mutation in this gene has been found in all 18 CJD patients tested from disease clusters in both Czechoslovakia and Israel. In addition, Gajdusek and his colleagues have found the defect in people of Slovak and Sephardic Jewish origin who live in countries outside Czechoslovakia and Israel. "We've got the same mutation in CJD patients from Poland, East Germany, and Tunisia, and in some patients from Greece," Dr. Brown said.
However, Dr. Brown says it is not known if the genetic defect actually causes the disease or if another agent, such as a virus or a second gene, is required. "The reason that the gene appears necessary but not sufficient," Dr. Brown explained, "is that a few relatives of Czechoslovak CJD patients who have the mutation, but are presently healthy, are getting beyond the age of risk." CJD peaks at about age 60. According to Dr. Brown, further study of these clusters will focus on the possibility of a coexisting environmental factor.
To date, this mutation has not occurred in anyone other than those with CJD or directly related by blood to someone with the disease. "It's beginning to look like this mutation in these groups is a fair marker for the disease," said Dr. Brown.
The National Institute of Neurological Disorders and Stroke, one of 13 of the National Institutes of Health in Bethesda, Maryland, is the primary supporter of brain and nervous system research in the U.S.
Last Modified August 7, 2009