Angelina Jolie's aunt has died of breast cancer less than two weeks after Jolie had a double mastectomy to avoid the disease.
Debbie Martin died at age 61 at a hospital in Escondido, California, near San Diego, said her husband, Ron.
Mrs Martin was the younger sister of Jolie's mother, Marcheline Bertrand, whose own death from ovarian cancer in 2007 inspired the surgery that Jolie described in her story in the New York Times.
According to her husband, Mrs Martin had the same defective BRCA1 gene that Jolie does, but didn't know it until after her 2004 cancer diagnosis.
"Had we known, we certainly would have done exactly what Angelina did," Mr Martin said in a phone interview.
Mr Martin said after getting breast cancer, Mrs Martin had her ovaries removed preventively because she was also at very high genetic risk for ovarian cancer, which has killed several women in her family.
Jolie (37) said her doctors estimated she had a 50pc risk of getting ovarian cancer but an 87pc risk of breast cancer. She had her breasts removed first, reducing her likelihood to 5pc.
She described the three-step surgical process "because I hope that other women can benefit from my experience."
The story spurred a broad discussion of genetic testing and pre-emptive surgery.
A message seeking comment from Jolie was not immediately returned.