Using a new technique to reprogram cells, scientists are growing neurons from people with Lou Gehrig's disease, a possible first step in understanding how the deadly illness develops.

Technically known as amyotrophic lateral sclerosis, the disease damages the nerve cells in the brain and spinal cord, eventually leading to death. The ALS Association estimates that as many as 30,000 Americans may have the disease at any given time.

"What we now have in the culture dish is cells that have the same genetic makeup as the ALS patient and they are the same cells that are affected by the disease," said Dr. Chris Henderson, co-director of the Center for Motor Neuron Biology and Disease at Columbia University.

That means that, for the first time, scientists hope to be able to observe the development of the disease in the cells and, from that, possibly begin studies of treatments.

"There is no way we could go to an ALS patient and take these cells," Henderson pointed out.

Instead, they used skin cells from two patients, aged 82 and 89, and were able to reprogram the cells into a type of adult stem cell, and from that into nerve cells, the researchers report in Friday's edition of the journal Science.

Co-author Dr. Kevin Eggan of the Harvard Stem Cell Institute said what they hope to do next is study the cells in the lab and compare them with cells of someone who doesn't have that disease.

ALS is a slowly developing disease and the test cells have not yet begun to show illness, they noted. But in similar studies in mouse cells the cultured neurons did develop the disease.

Dr. Lucie Bruijn, science director and vice president of the ALS Association, called the work a first step.

"This is the beginning," she said in a telephone interview. "It's a most important approach."

"Now we have to figure out whether these motor neurons are able to mature," she added. "For these to be useful for drug development we need mature motor neurons."

The researchers worked with a form of ALS that is caused by a defect in a single gene, a rare form of the disease.

But Henderson said that they even though the vast majority of cases are caused by different triggers, they hope to learn about the mechanism of the disease, how it develops after being triggered.

"Up until now, it's been impossible to get access to the neurons affected by ALS and, although everyone was excited by the potential of the new technology, it was uncertain that we would be able to obtain them from patients' skin cells," Henderson said. "Our paper now shows that we can generate hundreds of millions of motor neurons that are genetically identical to a patient's own neurons. This will be an immense help as we try to uncover the mechanisms behind this disease and screen for drugs that can prolong life."

The research was supported by the Harvard Stem Cell Institute, Project ALS, the SMA Foundation, MDA Wings Over Wall Street, the Spina and Bowen families, the New York Stem Cell Foundation, the National Science Foundation and the John D. and Catherine T. McArthur Foundation.