Michigan Technological University researchers have linked three genes to the most common type of amyotrophic lateral sclerosis (ALS), generally known as Lou Gehrig's disease.
Professor Shuanglin Zhang leads the team of mathematicians that isolated the genes from the many thousands scattered throughout human DNA. He notes that their discovery does not mean an end to ALS, but it could provide scientists with valuable clues as they search for a cure.
It can't come any too soon. Zhang started showing symptoms of the disease himself four years ago. He now breathes with support from a respirator and works at home with the aid of a research assistant and his wife, Qiuying Sha, an assistant professor and member of his research team.
"I felt very urgent to find the genes for ALS," he says.
"This is very nice work," said Xiaofeng Zhu, an associate professor of epidemiology at Case Western Reserve University's School of Medicine. "It's very challenging to map genes for complex diseases, and while many statistical methods have been developed, most don't work well in practice. Zhang's group has developed a method to detect genes and gene-gene interaction in complex diseases and provided evidence that it works.
"Their findings will need to be confirmed by other researchers, but I think this will be very useful for the investigators who are trying to find genes underlying complex diseases such as ALS," said Zhu.
According to the ALS Association, only about 10 percent of patients have familial ALS, a directly inherited form of the usually fatal neuromuscular disorder. The remaining 90 percent, including Zhang, are diagnosed with the sporadic form of the disease. While scientists have long suspected that genetics plays a role in sporadic ALS, they have had no evidence to back it up, at least until now.
Everyone has the three genes in question. But in people with sporadic ALS, they differ from those in people who don't have ALS.
The mathematicians were not surprised when they tracked down the genes' street address. "Everybody has 23 chromosomes, and the three genes on chromosomes 2, 4, and 10 interact," explained Sha. "If you have this combination of the three genes, you are at high risk of developing the disease."
"It's really exciting, especially because my husband has sporadic ALS," she adds. "Maybe they can find a cure by blocking the genes."
According to the ALS Association, approximately 30,000 Americans have ALS, and about 5,600 new cases are diagnosed every year. The disease destroys the nerves in the brain and spinal cord that control voluntary movement, eventually leading to paralysis.