Bedridden and unable to speak, Ken Melanson can only reach the outside world with the tip of his right index finger.

In the last few weeks the ravages of amyotrophic lateral sclerosis, also known as Lou Gehrig's disease, have paralyzed the finger Melanson uses to type on a computer, linking him with his family, friends and caretakers.

"He was just starting a life with (his) children," said Ken's mother, Joan Melanson. "To have this take over ..."

Three years ago, Ken, now 42, was diagnosed with the fastest-moving form of the disease which, in his case, first attacks the respiratory muscles, leaving patients unable to breath on their own. Without a respirator, he would quickly die.

A baffling disease

For families hit with ALS, hope is hard to hold onto, but researchers are identifying genes they believe cause the disease, and also point the way to a cure.

Melanson will not live to see that.

Almost three years ago was the first time Joan Melanson heard about ALS, a neurological disorder that would kill her then 40-year-old son in 18 to 24 months unless doctors put him on a ventilator to help him breathe.

The degenerative disease moves rapidly, destroying nerve cells in the brain and spinal cord. It kills motor neurons leaving the brain unable to control muscle movement. Eventually, patients die of respiratory failure.

Dr. Thomas Kwiatkowski Jr., a researcher at Massachusetts General Hospital in Boston, said research is moving faster than ever but progress is still relatively slow. The mapping of the human genome has provided researchers with a road map to search out abnormalities in genes. It also gives researchers a view of what a normal sequence of genes looks like for comparison.

"It now takes months to do what it used to take years to do," said Kwiatkowski.

While there is as yet no cure, scientists are getting closer to finding drugs to slow the progression of the disease which causes muscles to weaken and atrophy.

For families of those with ALS, the disease moves faster than any scientific breakthrough. Over the course of several years, ALS leaves people prisoners in their own bodies - their brains fully functioning but not able to move, speak or breathe alone - and kills its victims in two to five years.

"It's just a downhill battle," said Joan. "When you're dealing with ALS you can't be positive about anything."

To try and keep families going and bring attention to the heartbreaking disease, the ALS Association of Massachusetts and the Longfellow Club of Wayland are hosting the 9th annual Positive Spin for ALS to raise money to find cure.

Joan, a Natick resident, and her son Keith have helped raise money for the May 18 event. This year Keith will lead cyclists in a 50-mile ride named for his brother Ken.

A Natick High School graduate and Boston University alum, Ken had a successful career in financial services in Boston. He decided to move to Florida to get away from the cold winters so he could play more golf and fly rented airplanes, said Joan.

There was no sign trouble was in sight. ALS can strike anyone at any time regardless of family medical history. Typically, it strikes people in their prime - ages 40 to 70.

Researchers at the Massachusetts General Day Neuromuscular Research Laboratory are working with families to identify which genes are inherited. Ten years ago, Dr. Robert Brown identified one gene, superoxide dismutase1 or SOD1, which is linked to ALS.

Kwiatkowski said if researchers find families do not share the SOD1 gene, they look for inherited genetic markers and try to determine if the markers are near the genes thought to cause ALS.

In order to adequately research possible genetic links in families, researchers need blood samples from those suffering with the disease and their relatives. Due to the rapid progress of ALS and its high death toll, this is often difficult. Of the 600 families identified at the Day Laboratory, only 18 or 19 have had surviving members to do analyses on, said Kwiatkowski.

Ken did not inherit ALS, Joan said. In fact, most cases aren't genetic but researchers believe by studying patients' genes, they will be able to determine how the disease affects cells and ultimately shuts down muscle function.

Researchers are also looking at hundreds of DNA markers to determine which are most commonly passed on, as well as looking for mutations in the DNA sequence.

It's hard for Joan to visit her son in Juniper, Fla., where he lives with his wife and two sons, 3 and 41/2. Ken has been in bed for year and silenced by the disease for two years. He requires nursing care around the clock.

Joan has no way of knowing what is going through her son's mind as he lays in bed, trapped in his body. She tries to stay positive giving herself comfort in the fact that at least her family could prepare for the day her son is taken off his respirator.

"When you're with him you can almost sense his whole body is shutting down," she said. "This is something for the last three years that nobody needs to go through."

Hope through drug therapy

While Massachusetts General Hospital researchers are working to identify genes - of which at least four are responsible for ALS - Jamie Heywood's Newton company is studying existing drugs to determine if any can stop the progression of ALS.

Heywood started the ALS Therapy Development Foundation in 1999 to save his brother Stephen, 33, from the destructive disease. The nonprofit biotechnology company tests drugs in mice with ALS to determine which extend the lives of the animals.

Drugs for sickle cell anemia and HIV/AIDS look most promising to halt the disease's progression and are currently being tested in clinical trials in mice, said Heywood.

"The word 'cure' is a very tough thing to use," he said. "That's my goal to stop it right now. At the moment I would settle for Stephen not getting any worse."

If the tests in mice are successful, then clinical trials in humans are the next step. Often what works in mice doesn't in humans, said Heywood.

Kwiatkowski said researchers are also testing drugs in cultured cells. The mutated cells are tested with hundreds of drugs to see if any help the cells survive. If the cells are helped by drugs, then they are tested in mice and eventually humans.

In three years Kwiatkowski said there has been tremendous developments in technology, but ALS is extremely challenging. In the next few years he predicts researchers will identify two or three more genes that are linked to the disease.

It has been 20 years since researchers began trying to unravel the mystery of ALS at the Day Laboratory started by Brown.

"It's an incredibly challenging disease," said Kwiatkowski, who also treats ALS patients.

Treatments and cures take decades, and Kwiatkowski said patients don't have that kind of time. With more funding, he said, more work could be done to unlock the disease. Stem cell research is also a developing technology that could help ALS patients.

Though celebrities like New York Yankees baseball legend Lou Gehrig have brought attention to the disease, it's not enough. June 19 would have been Gehrig's 100th birthday.

As the disease progresses, Joan Melanson said her son Ken is angry and frustrated. He wants to know why and how he was stricken with such a terrible disease. Until he lost the use of his finger, he was keeping a journal that will one day be turned into a book for his young sons.

While Joan realizes she will lose Ken, she'll continue to fight for more money for ALS research.

"It's hopeless," she said. "We need the federal government to spend more money on research if we want anything done now. I wish we could make Ken get better. That's not going to happen for awhile."

The Positive Spin for ALS takes place on Sunday, May 18, and includes four concurrent bike rides with routes of 10, 25, 50 and 100 miles. The first ride, the 100-mile event, begins at 7 a.m. and the last, a 10-mile ride, begins at 11 a.m. All events begin and end at the Longfellow Club, 524 Boston Post Road, Wayland. For more information about the fund-raiser, see www.positivespinforals.org, or call the ALS Association Massachusetts Chapter at 781-326-8884. For information and directions to the Longfellow Club, call 508-358-7355.