Rev. Jesse Jackson has revealed he has Parkinson's disease. but plans to dedicate himself to treatment in hopes of fighting the disease's progression for as long as possible.
"My family and I began to notice changes about three years ago", Jackson writes. "For a while, I resisted interrupting my work to visit a doctor", Jackson said in a statement.
Jackson said he planned to advocate to find a cure for the disease, which he said "bested my father", strikes 60,000 Americans a year and afflicts 7 to 10 million people worldwide.
The 76-year-old, who once worked with Martin Luther King Jr for the cause of equal rights for African Americans, and now heads a Chicago non-profit organization, said it has become "increasingly hard to perform routine tasks".
"For 50 years that I've known Jesse Jackson, he has been an absolute voice of progressive thought, progressive development, representing the views and needs of the downtrodden".
The civil rights icon also released a Northwestern Medicine letter saying he was diagnosed in 2015 and has sought outpatient care.
Parkinson's disease occurs when certain nerve cells break down and reduce the amount of the chemical, dopamine, that sends signals to the part of the brain that controls movement, according to Webmd.com.
Rev. Martin Luther King Jr. gave Jackson a role in the Southern Christian Leadership Conference and was charged with establishing a presence for the organization in Chicago.
Rahm Emanual, the mayor of Chicago, said his "thoughts and prayers" are with Mr Jackson and his family. He was awarded the Presidential Medal of Freedom by President Bill Clinton in 2000 after he unsuccessfully ran for President in 1984 and 1988.
He said Friday in the letter that he is also working on a memoir.
Jackson declined further comment Friday.