Until now, the only way for people to get such genetic tests was to see a medical professional who would order a test and later deliver the results to patients. Often, patients were required to see a genetic counselor before getting a test.
The process for customers is simple. A customer spits into a tube and then mails it to 23andMe. The company’s lab extracts DNA from the saliva cells and tests it with probes that find genetic markers using a special chip for genotyping. In about six to eight weeks the company sends the customer an email saying the results are in. By logging onto an online account, the customer can see the report and its interpretation. It will include not just the genes for disease risk, but also reports of ancestry and results on things like how much the person is likely to weigh and whether alcohol will elicit flushing of the face, shoulders and neck, or even the entire body.
While some applaud the F.D.A.’s move, saying people do not always need the intervention of medical professionals and genetic counselors to learn their risk for certain diseases, others worry that it sets a dangerous precedent.
People often need genetic counseling before deciding they want to know if they are at risk for Parkinson’s disease, said James Beck, chief scientific officer of the Parkinson’s Foundation. “Once you get the test and read the results, there is no going back,” Dr. Beck said.
But Dr. Robert Green, a genetics professor at Harvard Medical School, said that most people who want to get such information on their own are able to handle it just fine. He has studied tests for Alzheimer’s risk in rigorous studies, asking if patients who simply got their results, without counseling, understood what they were doing and were able to handle the information. The vast majority were, he said. “I do not want to be cavalier,” Dr. Green added. “In some cases people did not realize what they were saying yes to and others did not realize the psychological impact it would have on them. There is some potential for distress, but it is much, much smaller than was anticipated.”
The test’s results do not by any means guarantee that a person will get the disease. Instead, they mean the disease is only more likely. With Alzheimer’s, for example, the test looks for a gene variant called ApoE4. Those with one copy of that gene have a threefold increased risk of Alzheimer’s. Those with two ApoE4 genes have a 15-fold increased risk. The actual risk depends on age, but even having two copies of ApoE4 does not foreordain the disease, Dr. Green emphasized.
From : The New-York times. Read full article here.