Justice Sandra Day O’Connor. Photo courtesy of the Supreme Court of the United States.

Retired Justice Sandra Day O’Connor is no longer making public appearances following a diagnosis of probable early-stage Alzheimer’s disease.

O’Connor, 88, announced in a letter on Tuesday that she has the beginning stages of dementia, and the condition is “probably Alzheimer’s disease,” report the Associated Press, the National Law Journal, the Atlanta Journal-Constitution and CNN. As a result, she is “no longer able to participate in public life,” the letter reads.

O’Connor said the diagnosis was made “some time ago.”

“While the final chapter of my life with dementia may be trying, nothing has diminished my gratitude and deep appreciation for the countless blessings in my life,” O’Connor wrote. “How fortunate I feel to be an American and to have been presented with the remarkable opportunities available to the citizens of our country. As a young cowgirl from the Arizona desert, I never could have imagined that one day I would become the first woman justice on the U.S. Supreme Court.”

O’Connor said she will continue living in Phoenix surrounded by family and friends.

The announcement follows an exclusive report by the Associated Press on Monday that said O’Connor made her last public appearance more than two years ago and is fully retired. She turned over her Supreme Court office this summer to the court’s most recently retired justice, Anthony Kennedy.

O’Connor’s son Jay O’Connor told the Associated Press that his mother has some challenges with short-term memory and she often uses a wheelchair. “When she hit about 86 years old, she decided that it was time to slow things down, that she’d accomplished most of what she set out to do in her post-retirement years, that she was getting older physically and her memory was starting to be more challenging, so the time came to dial back her public life,” he said.

Sandra Day O’Connor had retired in 2006 with the goal of helping her husband, John O’Connor, who was dealing with Alzheimer’s disease. John O’Connor died in 2009 at age 79.

O’Connor testified about her husband’s Alzheimer’s diagnosis before a Senate committee in 2008. “I submit to you that until you have actually stared Alzheimer’s in the face,” she said in her prepared remarks, “you cannot truly understand the deep sense of frustration, fear, helplessness and grief that accompany it.”

O’Connor’s announcement noted that she promoted civics learning after her Supreme Court retirement and said she would like to see funding for a nationwide civics education initiative. “It is time for new leaders to make civic learning and civic engagement a reality for all,” she wrote. “It is my great hope that our nation will commit to educating our youth about civics and to helping young people understand their crucial role as informed, active citizens in our nation.”

Chief Justice John G. Roberts Jr. issued a statement saying he was saddened to learn that O’Connor faces the challenge of dementia. But he said he was not surprised that O’Connor used her letter “to think of our country first and to urge an increased commitment to civics education.”

“Justice O’Connor is of course a towering figure in the history of the United States and indeed the world,” Roberts wrote. “She broke down barriers for women in the legal profession to the betterment of that profession and the country as a whole. She serves as a role model not only for girls and women but for all those committed to equal justice under law. Although she has announced that she is withdrawing from public life, no illness or condition can take away the inspiration she provides for those who will follow the many paths she has blazed.”