"Plundered Memories" by Zaven S. Khachaturian, in The Sciences (July–Aug. 1997), 2 E. 63rd St., New York, N.Y. 10021.

Alzheimer’s disease, the most common form least four million Americans, and care for of dementia in the elderly, currently afflicts at Alzheimer’s patients costs $100 billion a year. If no cure is found, warns Khachaturian, director of the Ronald and Nancy Reagan Research Institute of the Alzheimer’s Association, in Chicago, the number of Alzheimer’s patients will double every 20 years.

The insidious disease "quietly loots the brain, nerve cell by nerve cell, like a burglar returning to the same house each night," Khachaturian notes. Forgetfulness is typically the first symptom; then comes "more severe memory loss, followed by confusion, garbled speech and movements, hallucinations, personality changes and moods that can swing from anger to anxiety to depression." Death may not come for as long as 20 years after the first symptoms appear. (The period from onset to death now lasts, on average, eight years, but that is likely to lengthen, Khachaturian says, as the relatively healthy baby boomers age.) Patients are not the only victims: Alzheimer’s usually takes a toll, psychological and financial, on their families as well.

The disease was identified in 1901 by Alois Alzheimer, a German physician, but the era of modern research only began 75 years later with the discovery of a link between a biochemical brain defect (a deficiency of acetylcholine) and Alzheimer’s. Scientists next investigated the protein chemistry responsible for the "odd brain-tissue growths" that are now considered "the hallmarks of Alzheimer’s disease," Khachaturian says. More recently, researchers have turned their attention to the genetics involved.

In 1993, Allen D. Roses, a neurologist and geneticist at the Duke University Medical Center, identified a gene indicating a greater likelihood of getting Alzheimer’s. This year, investigators at Duke and Massachusetts General Hospital have reported finding a chromosome where a second "susceptibility" gene is located. When this second gene is finally pinpointed, Khachaturian says, then physicians should be better able to predict who is likely to get "late-onset" Alzheimer’s, the most common form of the disease.

This will present physicians with an ethical dilemma: whether to tell likely future victims of their fate when no cure is yet available. Khachaturian, however, thinks that the genetic approach is bringing the pieces of the puzzle together. He believes that a cure "will appear in the next five to 10 years."