Health news and commentary gathered by MedPage Today staff

Johnson shared his diagnosis in an exclusive interview with "GMA" co-anchor Michael Strahan.

Former NFL running back Chris Johnson announced that he was diagnosed with ALS, also known as Lou Gehrig's disease, in a "Good Morning America" interview.

Johnson was drafted by the Tennessee Titans in 2008

Former NFL running back Chris Johnson revealed that he has been diagnosed with sporadic Amyotrophic Lateral Sclerosis at the age of 39.