Doctors have known about the cruelly progressive and paralytic disease called amyotrophic lateral sclerosis for more than 100 years.

The public found out about it in 1939, when it forced the retirement of Lou Gehrig, New York Yankee first baseman, baseball's ever-smiling "iron man." The public soon learned that this is typically one of the most devastating of neuromuscular diseases, but even today, scientists do not know the cause and have no effective treatments for the affliction commonly called "Lou Gehrig's disease."

Gehrig had to quit baseball when he could no longer readily catch, hit or run. Still, he was able to walk out onto the field to be applauded and honored.

Soon he could no longer walk. His disease progressed rapidly. He died in 1941. This is the typical course of ALS.

First, generally, there is a little muscle weakness, often first in the hands. Then there is more limpness, weakness and stiffness, spreading to the arms and legs. It then gets hard to swallow and talk. There may be twitching, cramps and other discomforts.

There are exceptions to this swift, unrelenting progression, and many variations. Occasionally the disease progresses only very slowly or even halts. But most often death comes within three to five years.

The problem in all cases is that something -- doctors can still say no more than "something" -- has attacked the motor neurons, the motion-regulating nerves of the brain, brain stem and spinal cord. As these cells disintegrate, there is progressive wasting and atrophy of muscle cells.

On the average, the disease affects five to seven persons in every 100,000. It strikes about 1 1/2 times as many men as women, and often begins in early midlife. An estimated 17,000 to 20,000 Americans have ALS, and there are 5,000 new cases a year, says the Muscular Dystrophy Association, which coordinates charitable contributions for ALS research.

The Merck Manual, a condensed guidebook for physicians, says: "There is no specific treatment." An American Medical Association guide says: "Treatment is directed at easing symptoms and helping persons remain relatively mobile and independent." Some possible new treatments are being tried, with uncertain success so far.

Scientists may be close to identifying a specific gene -- or bit of DNA, the chemical of the genes -- responsible for ALS. Five to 10 percent of all cases are hereditary and continue to affect roughly half of all family members. This is one clue to the cause of ALS, but so far science cannot specifically say what triggers the disease in even these victims. In these and other patients, the triggering factor may be some chemical factor. Or a virus. Or physical trauma. Or something else.

Nonetheless, says Dr. Raymond Roos, director of the ALS-motor neuron disease clinic at the University of Chicago, "I feel optimistic. We have new technologies to attack problems like this. I can't believe that they won't have a major effect in the next five to 10 years."

More Information

To learn more about ALS, or to find out about support groups and other assistance, call the Muscular Dystrophy Association, (703) 823-5113.