BOSTON – Paul Cellucci, the former Massachusetts governor and U.S. ambassador to Canada, announced Thursday he has a relatively slowly progressing case of Lou Gehrig’s disease.

“I’ve had symptoms for four years,” the 62-year-old Cellucci said in a statement to The Associated Press. Despite some weakness, he said, “I am feeling quite well.”

Amyotrophic lateral sclerosis, or ALS, attacks the brain and spine and usually is detected after muscle weakness. It progresses to complete paralysis, is incurable and is always fatal.

Each year the disease, nicknamed for the New York Yankees player who died of it, kills about 5,000 Americans.

“I maintain a full and varied work schedule, love playing with my three grandchildren and attending my son-in-law’s NHL games, regularly complete six miles on an exercise bike, and enjoy the movies and dining out with friends,” Cellucci said.Cellucci works today as a Boston attorney, but he said that as a private citizen, he and his wife, Jan, were requesting privacy.

The statement said he is under the care of Dr. Robert H. Brown Jr., chair of Neurology at the University of Massachusetts Medical School and the University of Massachusetts Memorial Medical Center. Cellucci has always been proud of his blue-collar roots as the son of a car salesman and the west suburban town of Hudson. Equally proud of his resemblance to actor Robert DeNiro, Cellucci is a movie buff who regularly regaled the Statehouse press corps with his annual picks for Academy Awards.

But his lifelong experience in all levels of politics, as well as loyalty to those he served with, including the Bush family, is what took him to the highest echelons of government. The accomplishments have been all the more remarkable because he is a Republican from historically Democratic Massachusetts.

Cellucci attended Boston College and began his political career immediately after graduating in 1970. He was elected to the Hudson Charter Commission and, a year later, ran for selectman and won. He served while attending Boston College Law School, from which he graduated in 1973, before running successfully for state representative in 1976.

In 1984, Cellucci moved to the state Senate, still representing Hudson. In 1990, William F. Weld, a former federal prosecutor inexperienced in state politics, tapped Cellucci to be his running mate. The fiscally conservative, socially liberal tandem won the Statehouse for what would be a 16-year GOP run.

Cellucci replaced Weld as governor in 1997, when Weld resigned to make an unsuccessful bid to become U.S. ambassador to Mexico. Cellucci was elected governor outright in 1998. In a nod to his father’s work, Cellucci always insisted he and Weld be ferried in state cars that were Oldsmobiles.

During the 2000 presidential campaign, Cellucci was a surrogate campaigner for George W. Bush, Texas governor at the time.

His loyalty to the whole Bush family was rewarded in 2001, when Bush, as president, named him ambassador to Canada. Cellucci held the post until 2005, when he resigned and took a job with Magna Entertainment Corp., a Canadian racetrack company.