The granddaughter of former US president John F Kennedy, Tatiana Schlossberg, has died aged 35.

In an Instagram post from the John F. Kennedy Presidential Library and Museum, her family said she died on Tuesday morning, local time.

“Our beautiful Tatiana passed away this morning. She will always be in our hearts,” the family wrote.

Schlossberg, a climate change activist and environmental journalist, revealed in an essay published in The New Yorker in November that she had a rare form of terminal leukaemia.

She was the second child of JFK’s daughter, former US diplomat Caroline Kennedy, and the designer-artist Edwin Schlossberg.

In the essay, she criticised her cousin Robert F Kennedy Jr, the US Health and Human Services secretary, saying his policies could hurt cancer patients.

“As I spent more and more of my life under the care of doctors, nurses, and researchers striving to improve the lives of others, I watched as Bobby cut nearly a half billion dollars for research into mRNA vaccines, technology that could be used against certain cancers,” she wrote in the essay.

Schlossberg said she had been diagnosed in May 2024 at age 34 after her doctor noticed her white blood cell count was high following the birth of her second child.

It turned out to be acute myeloid leukaemia with a rare mutation mostly seen in older people, she wrote in the essay published on the 62nd anniversary of her grandfather’s assassination.

Her mother had already urged senators to reject RFK Jr’s confirmation as US health secretary.