Dane -- who shot to fame amid six seasons on the hit ABC drama "Grey's Anatomy," where he played Dr. Mark Sloan, affectionately known as "McSteamy" -- said his symptoms began over one year ago, when he began to experience weakness in his right hand.

The former "Grey's Anatomy" actor shared details of the progression of his symptoms and the emotional toll of living with the neurological disease.

ALS has robbed Dane of functioning in his right arm and is creeping through his left, the actor said in an emotional interview about the diagnosis he revealed in April.