If medical researchers discover that a subject in one of their studies is genetically predisposed to breast cancer or Parkinson’s disease, should they alert any relatives who might share the inherited risk?

Until now, researchers had little guidance on this quandary. Most will keep that information confidential if research subjects don’t want it shared. But they aren’t as sure what to do when those subjects die — a common occurrence in studies of cancer and other terminal diseases.

So last month, a federally funded panel featuring Mayo Clinic and University of Minnesota experts issued the first ethics guidance on the matter.

“What makes these issues so challenging is current bioethics, law, and research rules focus on protecting individuals. But genetics is about families,” said Susan Wolf, a co-author of the guidelines and a professor at the U’s Law School.

Navigating patient privacy rules is only part of the problem. Even if subjects approve the release of genetic information, relatives might not want to saddle themselves with the psychological burden of knowing they are predisposed to diseases.

Gloria Petersen, the Mayo co-author, said she knew of a few cases in which researchers shared the information with relatives of deceased research subjects. “In one instance, the investigators … searched for a family member [via Internet] … to share information that the family member was part of a family that had a hereditary condition.”

The upshot from the new guidelines: researchers in most cases should not initiate such talks with relatives, but should be ready to respond if relatives inquire.

The guidelines, published in the Journal of Law, Medicine & Ethics, do give researchers discretion to notify a relative if they believe it could “avert imminent harm.”

Petersen said researchers also can do better at notifying family members of the existence of genetic information that might be of interest to them. Otherwise, relatives are “usually in the dark,” Petersen said, because they don’t participate in the consent process their relatives undergo to participate in genetic studies.

Mayo has tried sending out newsletters notifying research participants in a pancreatic cancer registry and their relatives about the genetic information potentially available to them.

Some studies are designed to shield all results no matter who might be interested. But in others, Petersen said researchers should be asking study subjects during the consent process how they might want genetic information shared — and with whom.