Tatiana Schlossberg, the journalist and author who was a granddaughter of John F. Kennedy, has died after revealing she had been diagnosed with cancer, her family announced Tuesday.

She was 35.

"Our beautiful Tatiana passed away this morning. She will always be in our hearts," the family said in a social media post.

Schlossberg wrote in The New Yorker on Nov. 22 that she had acute myeloid leukemia, with a rare mutation called Inversion 3. She was diagnosed on May 25, 2024, when she gave birth to her second child and a doctor noticed her abnormally high white blood cell count and ordered further tests, she wrote.

She then spent five weeks at Columbia-Presbyterian Hospital in New York before beginning chemotherapy at home and later receiving a bone marrow transplant.

"During the latest clinical trial, my doctor told me that he could keep me alive for a year, maybe," she wrote. "My first thought was that my kids, whose faces live permanently on the inside of my eyelids, wouldn’t remember me."

She was the daughter of artist Edwin Schlossberg and diplomat Caroline Kennedy, the eldest child of John F. Kennedy.

Tatiana Schlossberg was an experienced and respected environmental journalist, having worked for The New York Times and contributed to publications such as The Atlantic and The Washington Post. Her book, "Inconspicuous Consumption: The Environmental Impact You Don't Know You Have," was published in 2019.

For one story, she completed a 30-mile, seven-hour cross-country ski race in Wisconsin.

Schlossberg wrote movingly about the psychological toll of dealing with terminal illness while raising a young family.

"Maybe my brain is replaying my life now because I have a terminal diagnosis, and all these memories will be lost. Maybe it’s because I don’t have much time to make new ones, and some part of me is sifting through the sands," she said.

In her essay, she reflected on the disbelief she felt upon hearing the news, given her healthy, active lifestyle — the day before giving birth, she had swum a mile in a pool.

But in her latest clinical trial, her doctor said he "could keep me alive for a year, maybe."

Schlossberg also criticized her cousin, Health Secretary Robert F. Kennedy, whom she said was "an embarrassment to me and the rest of my family" when he ran for president as an independent candidate in 2024.

As he was being confirmed to President Donald Trump's Cabinet, she was undergoing a clinical trial for CAR T-cell therapy.

"I watched from my hospital bed as Bobby, in the face of logic and common sense, was confirmed for the position, despite never having worked in medicine, public health, or the government," she wrote.

She added that, given Kennedy's skepticism of vaccines and his public doubt over their safety, Schlossberg worried that, now that she was severely immunocompromised and needed to retake her childhood vaccines, she may not be able to access them.

This article was originally published on NBCNews.com