San Francisco 49ers legend Dwight Clark has announced via Twitter that he is suffering from amyotrophic lateral sclerosis (ALS).
I wanted to share some unfortunate news: I have ALS. https://t.co/RqU0fFT98g— Dwight Clark (@DwightC87) March 20, 2017
The neurodegenerative disease -- also known as Lou Gehrig's disease -- disrupts the connection between the brain and the muscles and can eventually leave sufferers paralyzed but with brain function.
Clark played as a wide receiver for the 49ers from 1979 to 1987. As a player he is best remembered for "The Catch," in the 1982 NFC Playoffs against the Dallas Cowboys in the final minute of play which sent San Francisco on to the Super Bowl.
You can read his full letter, My Story, where he said he experienced constant pain in his neck since his football days and in September 2015 developed weakness in his left hand. Months later he was diagnosed with ALS.
"While I'm still trying to wrap my head around the challenge I will face with this disease over the coming years, the only thing I know is that I'm going to fight like hell and live every day to the fullest," Clark wrote. "In addition to losing strength in my left hand -- which makes opening a pack of sugar or buttoning my shirt impossible -- I have now experienced weakness in my right hand, abs, lower back and right leg. I can't run, play golf or walk any distances. Picking up anything over 30 pounds is a chore. The one piece of good news is that the disease seems to be progressing more slowly than in some patients."