(NBC News) — John Driskell Hopkins, a founding member and the bassist for the country music group the Zac Brown Band, says he has been diagnosed with Lou Gehrig’s disease.

Hopkins, 51, announced the diagnosis in a video posted to the band’s official YouTube channel Friday. He told viewers he had some “tough news” to share.

Amyotrophic lateral sclerosis, or ALS, sometimes known as Lou Gehrig’s disease, targets the nervous system, weakening muscles and limiting physical function.

Hopkins said he had noticed issues with his balance for several years and that his hands would become stiff. He said he met with doctors and that “after careful analysis by some of the country’s top neurologists, I have been diagnosed with ALS.”

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