Kara Kennedy Allen, the daughter of the late Sen. Edward Kennedy, D-Mass., died suddenly at a Washington, D.C., gym on Friday, NBC News reports. She was 51.
No details were given about her death, but NBC News reports that family members have been told a heart attack was suspected. Kennedy Allen is a lung cancer survivor, and has been in remission for a number of years.
Kennedy Allen maintained a private life. She served on boards of nonprofits and was once a television producer.
Kennedy Allen, who is divorced, is the mother of two teens.