Prenatal genome sequencing raises ethical issues for gene sequencing labs and clinical labs, since a baby’s genetic information may present lifelong consequences for that individual
Pathologists and clinical laboratory managers will be interested to learn that another milestone in genetic testing was reached earlier this year. A geneticist at the University of California at Davis, has sequenced the whole human genome of his unborn baby, the first time this feat has been accomplished.
Notably, it was geneticist and graduate student Razib Khan of the UC Davis School of Veterinary Medicine who sequenced his unborn son’s genome during the third trimester of pregnancy using a sample of the fetus’ placenta. This is the first healthy person born in the United States with his entire genetic makeup deciphered prior to birth, noted a recent story published by the MIT Technology Review.
Genticist Admitted to ‘Pushing the Envelope’
There was no real medical reason for Khan to learn his son’s DNA code, noted the MIT Technology Review article. Saying that sequencing his son in utero “was more cool than practical,” Khan admitted that he likes “pushing the envelope” and did it to show where gene sequencing technology is headed.
Baylor College of Medicine Gearing Up to Provide Fetal Genetic Testing
Art Beaudet, M.D., Chairman of Molecular Genetics at Baylor College of Medicine, agrees with Khan. Beaudet noted that because sequencing DNA is becoming both cheaper and easier, its use in pregnancy is likely to become a way for parents to get a broad view of a fetus’s health.
“In five years we will be offering genome sequencing for all routine pregnancies in the first trimester,” he predicted. Baylor plans to offer exome sequencing, which decodes key parts of the genome, during pregnancy for some couples.
Rapid Acceptance of Fetal Gene Sequencing
“It’s unprecedented in medical testing how fast this has gone from lab research to acceptance,” observed Dian Bianchi, M.D., Executive Director of the Mother Infant Research Institute at Tufts University Medical Center in Boston.
Some doctors strongly oppose doing predictive testing on children for diseases that only occur in adults. Sequencing the genome of fetuses is even more controversial. Fetuses cannot give consent for this test, which may have lifelong consequences. Additionally, the discovery of a bad mutation could lead parents to an “irrevocable action,” such as abortion, observed Bianchi, pointing out that DNA isn’t always destiny, as sometimes a person has a genetic defect but never has symptoms.
Have Good Clinical Reasons to Sequence Fetal DNA
This is one reason why physicians are reluctant to explore a fetus’ DNA makeup without good reason. Dennis Lo, M.D., a professor of Medicine and Chemical Pathology at the Chinese University of Hong Kong and Director of the Li Ka Shing Institute of Health Sciences, believes that, as fetal DNA sequencing advances, test makers should restrict themselves to reporting just the 20 or so most common serious diseases.
“We are going to face the challenge of what do you look for and how do you counsel women,” he said in 2013 MIT Technology Review report. “I think we must use the technology in an ethical fashion and should refrain from analyzing things that are not life-threatening. Like predisposition to diabetes when someone is 40 years old. We don’t even know what medicine would be in 40 years, so why worry the mother about that?”
FDA Puts Brakes on Marketing Direct-to-Consumer DNA Tests
The U.S. Food and Drug Administration has halted marketing direct-to-consumer DNA tests, like the one offered by 23andme. Jay Shendure, M.D., Ph.D., Associate Professor and researcher in human genomics at the University of Washington in Seattle, also predicts, however, that this gene sequencing test will come into common use, because the cost of gathering DNA data is plummeting.
Khan Used Free, Online Promethease Software to Interpret Son’s DNA
Khan initially used the Chorionic Villus Sampling (CVS), which is 98% accurate in identifying chromosomal problems such as Down syndrome and other genetic disorders. Eventually, Khan realized it was easier to sequence the whole genome, than test for specific genes. He convinced a fellow student to put his son’s genetic sample in a free slot in a high-speed sequencing machine used to study DNA in various animal species.
Khan organized and interrupted the 43 megabytes of raw gene data produced by the sequencing machine using the free genetic database available online at Promethease. This software crunches DNA data into reports that identify genetic variants of interest and their medical meaning. It is a do-it-yourself toolkit that allows interested individuals to explore DNA without a prescription.
Although Promethease identified 7,000 gene variants in baby Khan’s genome, the MIT Technology Review story noted that there were actually few surprises—he is just a regular kid.
Low-cost Genetic Testing a Boon for Pathologists and Genetics Labs?
Growing interest in sequencing fetal genomes−now that the price is so low−may be a boon for pathologists and genetic sequencing labs, but it also presents ethical issues for clinicians. Before genetic sequencing of embryos can become routine, professional groups such as ACMG will need to develop guidelines and ethical standards.
In the meantime, the falling cost of gene sequencing and easier access to gene sequencing instruments may encourage other scientists who are expectant fathers and mothers to do whole-genome sequencing on their unborn fetuses.
—by Patricia Kirk