It affects about 850 people locally today, including 51-year-old Paul Wensel.
Paul was always on the go, until about a year and a half ago, he got a slight limp.
"I was working 60 hours a week, I just figured it was a little glitch," Wensel said.
Unfortunately, it was ALS.
It affects the nerve cells.
As it progresses, patients aren't able to move their muscles.
In Paul's case, just one year after being diagnosed, he could no longer move his legs.
"I can wiggle a couple of my toes, but there is no movement in my legs at all," Wensel said.
And from the time Lou Gehrig got the disease until now, there has been little progress.
Average life expectancy then was 2 to 4 years, now it's 2 to 5 years. But there has been progress in support.
The ALS Association of Philadelphia helps patients get medical equipment like a lift for Paul and access ramps. They also help families navigate the health system.
"We have five social workers who work tirelessly to assure they get benefits they are entitled to and that they need," Jim Pinciotti of the ALS Association of Philadelphia said.
Pinciotti also says there is also hope for treatment.
A new drug is now being tested and genes have been identified.
Paul hopes if not for a cure, at least a therapy to make life a bit easier.
If you would like to get involved with the ALS Association:.
www.alsphiladelphia.org or 1-877-GEHRIG-1
They need volunteers and there are several fundraisers coming up, including one with the Philadelphia Phillies.