Story highlights Nearly 1 million people have Parkinson's disease in the United States

The condition causes tremor, stiffness and difficulty coordinating movement

(CNN) Civil rights activist the Rev. Jesse Jackson said Friday that he has been diagnosed with Parkinson's disease. A neurological disorder with no cure, Parkinson's can cause tremors, stiffness and difficulty balancing, walking and coordinating movement.

"My family and I began to notice changes about three years ago," Jackson wrote in a statement. "After a battery of tests, my physicians identified the issue as Parkinson's disease, a disease that bested my father."

Jackson added that "recognition of the effects of this disease on me has been painful."

He also said he sees his diagnosis as "a signal that I must make lifestyle changes and dedicate myself to physical therapy in hopes of slowing the disease's progression."

Born in Greenville, South Carolina, the 76-year-old is a two-time Democratic presidential candidate. Highlights of his career include participating in civil rights demonstrations with the Rev. Martin Luther King Jr., negotiating successfully for the release of three US soldiers who had been held in Yugoslavia and receiving the Presidential Medal of Freedom from President Bill Clinton.