Another study of genetic diagnosis, also published Wednesday, shows that analyzing more than 21,000 genes can often find the cause of unexplained cases of severe mental disability.
Researchers reported in the New England Journal of Medicine that in 16 of 100 patients, they were able to identify genetic mutations that caused the condition. The mutations were not inherited from parents, but rather occurred spontaneously in the egg or sperm.
Joris Veltman, a study author from the Radboud University Nijmegen Medical Center in Nijmegen, the Netherlands, said such an analysis can help families understand the cause and prognosis of the disease. Finding a non-inherited mutation "tells the parents that this was just bad luck, and tells the mother that she is not to blame for this, nothing went wrong during the pregnancy," he wrote in an email. It also reveals that the chance of the same mutation affecting a future child would be very low, he said.
Dr. Leslie Biesecker, chief of the genetic disease research branch at the National Human Genome Research Institute, who did not participate in the study, said he expected scientists will be able to identify mutations in a higher fraction of cases as more research is done.
AP Science Writer Malcolm Ritter contributed to this story from New York.
New England Journal of Medicine: http://www.nejm.org
Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.