Civil rights activist the Rev. Jesse Jackson announced Friday that he has been diagnosed with Parkinson’s disease.

“My family and I began to notice changes about three years ago,” Jackson, 76, wrote in a statement. “After a battery of tests, my physicians identified the issue as Parkinson’s disease, a disease that bested my father.”

He added that “recognition of the effects of this disease on me has been painful, and I have been slow to grasp the gravity of it.

“For me, a Parkinson’s diagnosis is not a stop sign but rather a signal that I must make lifestyle changes and dedicate myself to physical therapy in hopes of slowing the disease’s progression.”

The two-time presidential candidate, who received the Presidential Medal of Freedom from President Bill Clinton, took part in civil rights demonstrations with the Rev. Martin Luther King Jr. He also negotiated successfully for the release of three US soldiers who had been held in Yugoslavia.

In 2014, he spoke out about the shooting death of 18-year-old Ferguson, Mo., resident Michael Brown that led to protests and sparked national debate about race and law enforcement.

Parkinson’s disease is a neurological disorder with no cure that is caused by the death of brain cells that contain dopamine, a neurotransmitter required for communication within the brain. Losing dopamine neurons is a normal part of aging, but those with the disease lose many more than usual.

“I am far from alone. God continues to give me new opportunities to serve,” Jackson said. “This diagnosis is personal but it is more than that. It is an opportunity for me to use my voice to help in finding a cure for a disease that afflicts 7 to 10 million worldwide.”

He noted that about 60,000 Americans are diagnosed with Parkinson’s every year.

“I will continue to try to instill hope in the hopeless, expand our democracy to the disenfranchised and free innocent prisoners around the world,” he said.

“I’m also spending some time working on my memoir so I can share with others the lessons I have learned in my life of public service. I steadfastly affirm that I would rather wear out than rust out,” he said, thanking his family and friends for their support.