Parents who learn that they carry a breast cancer-linked gene mutation will usually pass this information along to their children, and will often do so long before any medical interventions are necessary, a new study confirms.

“Our results indicate that the majority of children of BRCA mutation carriers are learning of their potential genetic risk of cancer many years before preventive interventions are recommended and without input from healthcare providers,” Dr. Angela R. Bradbury and colleagues from the University of Chicago write.

People with either the BRCA1 or BRCA2 mutation are instructed to consider more frequent cancer screening, certain drugs for prevention, and in some cases surgery to remove their breasts or ovaries, Bradbury and her team note. But none of these approaches are recommended until the mutation carrier reaches age 25, so most authorities recommend that genetic testing shouldn’t be conducted until adulthood and patients shouldn’t tell their children that they too may carry the mutation until they are 18 or older.

But studies have shown that about half of people who learn they have a BRCA mutation will tell their minor children about it anyway, Bradbury and her team add.

To investigate further, the researchers surveyed 42 BRCA mutation carriers who reported telling their children about their test results. All children were younger than 25 when the disclosure occurred.

Twenty-three of the parents surveyed said they had talked with at least one of their children about hereditary cancer risk, the researchers found, while 42 of the 86 children included in the study had learned about either the test results or their genetic risk of cancer.

Parents rarely discussed their decision to disclose the results with a medical professional; just 14 percent talked with a doctor and 21 percent consulted a genetic counselor.

On average, the children were about 18 when their parents told them of the gene mutation or hereditary cancer risk. While parents rarely discussed the mutation with young children, two children under 10 years old were informed.

About half of the parents said their children reacted negatively to the news, and in some cases they felt the children didn’t understand the information.

Twenty-two percent said the information made their child concerned or anxious, while 28 percent reported crying and fear. Sixty-five percent said giving their children the information didn’t affect their relationship, while 22 percent said it strengthened their relationship.

The researchers found that women were more likely to disclose the genetic information to their offspring than men were. Women who underwent preventive surgery were also more likely to tell their children, possibly to help explain why they had the operation.

The investigators conclude: “The data suggest limited involvement of clinicians in parents’ decisions to disclose results to young family members, that some offspring may not fully understand the information shared and that there is a potential for initial adverse reactions among offspring in response to parent disclosures.”

More research in this area is needed to better understand the impact and long-term psychological consequences of genetic disclosure on these children, they add.

SOURCE: Journal of Clinical Oncology, August 20, 2007.