ALS strikes 5,000 Americans each year. The disease involves the progressive death of motor neurons, the nerve cells that transmit impulses from the brain and spinal cord to the muscles. As the condition advances, sufferers lose the ability to speak, swallow or breathe. Though a few survive 20 years or more (as the British astrophysicist Stephen Hawking has), most die within five years.
By examining tissue from 18 ALS families, a team led by Dr. Robert Brown of Massachusetts General Hospital found that sufferers shared a number of mutations in the gene that enables the body to produce an enzyme called superoxide dismutase, or SOD. In a healthy person, that enzyme protects cells from toxic molecules known as free radicals. The new findings suggest that when people inherit a defective SOD gene, they fail to produce the enzyme properly and their motor neurons end up defenseless against free-radical damage.
It stands to reason that free radicals might play a key role in ALS-hereditary or not-and that chemicals that neutralize them (the so-called antioxidants) might provide effective treatments. “We haven’t slain Goliath,” says Teepu Siddique, a Northwestern University neurologist who helped direct the new study. “But we certainly feel like a David who’s been introduced to the slingshot.”
