Fort Lauderdale, Fla. ? After three decades of work, scientists said Sunday they have identified two human genes that can cause multiple sclerosis, illuminating a new road toward a treatment for the debilitating nerve disease.

Two new studies confirm what MS experts and patients have long suspected: The disease can be inherited and is caused by the body’s immune system attacking itself.

By finding two genes that produce the malfunction, a Miami co-author of the studies said researchers could now develop drugs that block the disease before it starts.

“This tells us very clearly where to look,” said Margaret Pericak-Vance, genetics director at the University of Miami School of Medicine. “This is going to be a breakthrough and open the door for new pathways and new therapies.”

So far, medicine has had little to offer the nation’s 400,000 MS patients. Six drugs on the market only slow MS or ease symptoms.

The unpredictable disease typically strikes between ages 20 and 50, causing a range of ailments from mild muscle weakness to complete paralysis. It’s more common in women than men, and more prevalent among those of European descent.

The disease strips the coating from nerve cells, disrupting their ability to carry signals from the brain. Scientists believe the disease strikes people who have gene defects that make them susceptible to something – possibly viruses, bacteria or heavy metals – that triggers the condition.

The two studies, published in the New England Journal of Medicine and Nature Genetics, pegged the disease to faults in genes called interleukin-2 and interleukin-7, which help control T-cells, antibodies that attack invaders in the body.

With these findings, researchers can do blood tests to identify people with the flawed genes and begin to develop drugs that counteract the effects.