Former NFL star Chris Johnson reveals ALS diagnosis at 39

Former NFL running back Chris Johnson, a three-time Pro Bowl selection drafted by the Tennessee Titans in 2008, has revealed he was diagnosed with ALS (Lou Gehrig's disease) last year at age 39. Johnson disclosed the diagnosis in an exclusive interview with Good Morning America co-anchor Michael Strahan, stating his doctors believe his is a case of sporadic ALS, which accounts for the vast majority of ALS cases. He noted he had no family history of the disease and first noticed symptoms while otherwise living an active life with his wife and four children.