Genetic tests find skeletons like incest in the family: Study

By Dr. Ananya Mandal, MDFeb 13 2011

Researchers at Baylor College of Medicine in Houston have developed sophisticated DNA analyses that can detect disabilities as birth defects, epilepsy or developmental delays. They note that about 25 percent of genetic material inherited from their mother was the same as material inherited from their father. This denoted incest. This has triggered ethical debates over how these inadvertent findings should be handled.

The team had been performing tests over few months on patients and they noted fewer than 10 cases of consanguinity. This means inheriting the same gene variations from two closely related people, said Dr. Arthur L. Beaudet, chairman of Baylor’s department of molecular and human genetics. However, wider use of such testing in children with disabilities is expected to identify additional cases of incestuous parentage. In many cases, researchers discovered that children had parents who were father and daughter or brother and sister.

Beaudet and colleagues wrote in the current issue of The Lancet, “Although such revelations might provide important diagnostic clues to the underlying disorders, they also raise important legal and ethical concerns.” Beaudet said children of first-degree relatives face a risk of disability up to 50 percent higher than that of children born to unrelated moms and dads. Beaudet, a paediatrician also trained in genetics added, “It used to be in the past that occasionally we would be suspicious, or occasionally a child would be brought in, and social services would be involved and tell us… But now we see a child where we don’t suspect that, and the lab result comes back and says…this child is the product of mating between two very closely related individuals.” Such revelations could cause harm “in the form of stigmatization, emotional distress and criminal accusations,” Beaudet and his co-authors wrote in the correspondence appearing in the journal.

The team has suggested that the American College of Medical Genetics, American Society of Human Genetics and European Society of Human Genetics draft practice guidelines addressing consent, disclosure and reporting.

According to Amy L. McGuire, an attorney who is an associate professor of medicine at Baylor’s Center for Medical Ethics and Health Policy, as soon as geneticists learned that incest appeared to be an issue for some of their young patients, a committee of ethicists, geneticists and attorneys began “to think through the issues, looking at the laws and some of the ethical considerations related to this and coming up with a policy that the hospitals can use to manage these cases when they come up.” She added even if evidence points to the same, “you can’t tell from the test definitively who the biological father is… If there’s multiple first-degree relatives, you wouldn’t be able to discern whether it was dad, or a brother. That’s what makes it difficult to develop general, definitive practice guidelines. Like most areas of medicine, it really depends on the circumstances of the case before you.”

Beaudet said it rare to come across such an incident. “Mostly we’re dealing with young girls in the home who are probably being sexually abused by their father… They’re carrying the babies to term, and they’re probably being told that if they tell anyone about anything, they’ll be harmed or injured… It’s not so unusual to have a girl have two or three children with her father… If you discover the first one, there’s some potential to stop the second one.” Beaudet and his colleagues decided to go public to discourage, if not stop incest. “Maybe the people who are the offenders are not amenable to the kind of education we’d like to get out, but ... if this happens and there’s a child born, it may well uncover this and get the offender in trouble.”

According to Lynn Jorde, president of the American Society of Human Genetics, a society committee that deals with social, legal and ethical issues will consider the legal and ethical ramifications of “detectable incest, especially when there is the possibility that someone may have been abused as a minor.” He said it could be “scientifically important to know...if we take a large collection of children with, say, developmental delay, how often do we see incest or just consanguinity?”

The American Society of Reproductive Medicine already has been dealing with issues of consanguinity that could arise if children of sperm donors or egg donors met and unknowingly mated with their half-siblings. ASRM guidelines advised limiting pregnancies per sperm or oocyte donor to 25 within a population of 800,000.