The National Institutes of Health quietly blocked public access to databases of patient DNA profiles after learning of a study that found the genetic information may not be as anonymous as previously believed, The Times has learned.
Institute officials took the unusual step Monday and removed two databases on its public website. The databases contained the genetic information of more than 60,000 cooperating patients. Scientists began posting the information publicly eight months ago to help further medical research.
Creators of the databases had taken steps to mask the identities of the patients, summarizing and aggregating the genetic information. However, the independent study released today reported that a new type of DNA analysis could confirm the identity of an individual in a pool of similarly masked data if that person's genetic profile was already known.
Such a confirmation could reveal patients' participation in a study about a specific medical condition, denying them their presumed confidentiality, experts said.
For The Record
Los Angeles Times Saturday, August 30, 2008 Home Edition Main News Part A Page 2 National Desk 1 inches; 43 words Type of Material: Correction
DNA: An article in Thursday's Section A about the potential for privacy breaches in publicly available DNA databases misspelled the name of the head of the genetic studies oversight body of the National Institutes of Health. She is Dr. Elizabeth Nabel, not Nable.
"It's possible, but the likelihood is quite low" that a patient's privacy could have been violated, said Dr. Elizabeth Nable, head of the institute's genetic oversight body, in an interview Thursday evening. "We wanted to err on the side of caution."
The unexpected scientific advance and the institute's swift reaction highlight a growing tension in the field of genetic research, several experts said. Researchers favor public access to large pools of such data to speed the pace of medical innovation, but the privacy and public policy implications of such moves are still being understood.
Most patients in the databases signed consent forms after being promised their information would remain private, Nable said. Since the databases became publicly available in January, 140 individuals or institutions have downloaded the data. There is no way to retrieve or prevent the circulation of the information already released.
The Wellcome Trust, a British charity that maintains large online genetic databases for medical research, is taking similar steps, Nable said. Trust officials could not be reached for comment.
Nable said that there is no known violation of patient privacy and that a "nefarious person" would have to already know a person's genetic profile and use a complex algorithm to confirm a patient's existence in one of the databases.
Still, some in the field portrayed the health institute's move as a significant sign that developments in genetic science are quickly outpacing the field's existing privacy protections.
"It's a big deal," said Russ Altman, chair of the bioengineering department at Stanford and editor of the journal Bioinformatics. "They worked very hard on [the new privacy protocol] and something has come up that has thrown it into doubt."
Fred Bieber, a geneticist at Harvard Medical School, said: "The lesson is that with enough genetic information, it's becoming easier to identify individuals even though their identities are presumed to be" anonymous.
The study that sparked the move, published in today's edition of the journal Public Library of Science, revealed the ability of a new type of forensic DNA analysis to identify a person's DNA even if it were found in minute quantities and mixed with that of hundreds of other people.
Currently, such highly mixed genetic samples are usually discarded as meaningless.
The authors alerted the health institute to the study's conclusions last month. They hint at the privacy implications only in the paper's final paragraphs: "Our findings show a clear path for identifying whether specific individuals are within a study based on summary level data."
Dr. Dave Craig, a researcher at the Translational Genomics Research Institute and lead author of the study, said the innovation "opens a Pandora's box of questions."