Fathers could be passing on a genetic mutation to their daughters that further adds to their inherited risk of ovarian cancer, new research suggests.
A study of about 10,000 families impacted by ovarian cancer found a genetic mutation passed down through the father's X chromosome is entirely separate from the BRCA1 and BRCA2 mutaions which are passed on by both mother and father.
This mutation was also found to be associated with higher rates of prostate cancer in fathers and sons.
Published in journal PLOS, the researchers said the findings of the 30-year study could explain why some families have multiple members affected by the disease.
"A family with three daughters who all have ovarian cancer is more likely to be driven by inherited X mutations than by BRCA mutations," said Kevin Eng, a professor of oncology at Roswell Park Comprehensive Cancer Center in Buffalo, New York.
Using the Familial Ovarian Cancer Registry, researchers looked at data collected over 30 years and collected information about pairs of granddaughters and grandmothers. They then sequenced portions of the X-chromosome from 186 women affected by the cancer.
Women born to fathers whose mother had been affected by ovarian cancer were twice as likely to develop the disease, compared to those who inherited the disease from their mother's side, data showed.
"The paternal-lineage women had 2.04 times the risk of maternal-lineage women," the authors wrote.
Women carrying this previously unknown mutation on the X-chromosome also developed the cancer more than six years earlier than average.
"We observed a significant acceleration in the development of disease in granddaughters with an affected paternal grandmother versus maternal grandmother," wrote the authors.
Professor Georgia Chenevix-Trench of the QIMR Berghofer Medical Research Institute said it had always been known ovarian cancer could be inherited through the father.
What the new research does suggest is that there might be something specifically on the X chromosome that adds to that risk, the Australian geneticist said.
However she added more research is needed, noting a previous and much larger study failed to show any association between the specific mutation variation the authors refer to and disease.
"What's interesting about this paper, if it's correct, is that there seems to be something extra on the X chromosome that the paternal grandmother will pass on to her son and that will always be passed on to his daughters," Professor Chenevix-Trench told AAP.
"It doesn't all of a sudden mean most of a woman's risk of ovarian cancer is inherited through the father," she said.
"It just means there might be a little bit of additional risk through your father."
