‘Defective gene may cause Alzheimer’s’

Press, 25 February 1987, Page 12

‘Defective gene may cause Alzheimer’s’

By

CATHERINE ARNST

NZPA-Reuter Boston

An international team of scientists bas said that they have discovered the location of a defective gene that is the most likely cause of an inherited form of Alzheimer’s disease. “This is the first time we have a direct route towards the cause of Alzheimer’s,” said Dr James Gusella, the senior author of the scientific paper on the discovery. ; “This is an extremely fundamental and important discovery," said Dr Michael Shelanski, chairman of the Department of Pathology at Columbia University, and a leading expert on Alzheimer’s disease. “We can now pinpoint the cause of the disease, and that is the first step towards an eventual cure.”

Dr Gusella, director of the neurogenetics laboratory at Massachusetts General Hospital, said that the discovery could lead to a diagnostic test in three to five years for. the now-incurable disease and, ultimately, to an effective treatment.

At present, a positive diagnosis of Alzheimer’s disease can only be made after death by testing the patient’s brain tissue.

Dr Gusella said his team, which included doctors from Italy, Germany and France, found the defect by studying four large families over several generations. They had inherited a form of the disease known as familial Alzheimer’s disease, which accounts for about 10 to 20 per cent of all cases.

The scientists discovered that one of the

body’s 23 chromosomes, chromosome 21, carried a defective gene that was found in all members of those families who inherited the condition.

Dr Peter St GeorgeHyslop, a research fellow at the Department of Neurology at Massachusetts General Hospital, and a principal author of the report, said that because the disease process was very similar in both inherited and sporadic forms of Alzheimer’s disease the same defective gene most likely caused both types.

Alzheimer’s disease is a degenerative disorder of the central nervous system in which patients gradually lose their memory, reasoning, orientation and judgment. The disease generally strikes victims in their 60s and 70s and has claimed an estimated 2.5 million adults in the United States alone, about 9 per cent of the over-65 population.

Dr Robert Katzman, a member of the medical and scientific advisory board of the Alzheimer’s Disease and Related Disorders Association, said that “over the long term, if we can find out the exact gene that causes familial Alzheimer’s disease, we may be able to find a way to either prevent or cure the disease.

“We now have a tool to determine where that gene is.” A spokeswoman for the Alzheimer’s Disease Association in Chicago said that although the discovery is “an important scientific breakthrough, it should not be considered a clinical breakthrough.” She said the discovery would have no meaning

for patients for at least five years. The team which made the discovery spent three years studying data and blood samples from the four families in West Germany, Italy, Canada and the United States.

The findings were published in “Science” magazine.

Dr Ronald Polinskv of

the National Institutes of Health, who collaborated on the research, said the next step would be to examine more families to confirm the results and narrow the region of the chromosome until the exact disease-causing gene was found.

That would probably take at least three morte years, he said.