Just two days before his 77th birthday, musician Neil Diamond canceled the third leg of his 50th anniversary concert tour Monday and announced his retirement from the road following a diagnosis of Parkinson’s disease.

“The onset of the disease has made it difficult to travel and perform on a large scale basis but will allow Mr. Diamond to continue his writing, recording and development of new projects,” said a press release posted to Diamond’s official website.

“It is with great reluctance and disappointment that I announce my retirement from concert touring. I have been so honored to bring my shows to the public for the past 50 years,” said Diamond in the release.”My sincerest apologies to everyone who purchased tickets and were planning to come to the upcoming shows.”

What, exactly, is Parkinson’s disease?

“Parkinson’s disease is a neurologic disorder, characterized by slowness of movement, tremors, rigidity of the muscles, and balance difficulties,” said Dr. J. Antonelle de Marcaida, director of the Chase Family Movement Disorders Center. “It’s caused by a part of the brain degenerating. There’s a dopamine deficiency that leads to lack of mobility. So this limitation of mobility may be what is causing him to have trouble doing a world tour.”

For those with a Parkinson’s diagnosis — including Diamond — advances in treatment are reasons to provide hope.

“We have 24 medications for Parkinson’s disease,” she said. “Research is strong in Parkinson’s disease and at Hartford HealthCare we just launched our surgical program – deep brain stimulation – which almost turns back the clock and allows (patients) to continue to do all these things that are important to them.”

Diamond plans to continue as a working musician, though not in a touring capacity. Diamond said he’s grateful to his fans for half a century of support.

“My thanks goes out to my loyal and devoted audiences around the world,” he said. “You will always have my appreciation for your support and encouragement. This ride has been ‘So good, So good, So good’ thanks to you.”

Learn more about the Chase Family Movement Disorders Center here.