FDA approves home test for Alzheimer's genetic risk

The U.S. Food and Drug Administration has approved the first home genetic tests for 10 health risks, including Parkinson’s disease and late-onset Alzheimer’s.

The approval -- granted to the California-based company 23andMe Inc. -- could help test users make lifestyle choices or spark important discussions with health care providers, the FDA said.

“Consumers can now have direct access to certain genetic risk information,” Dr. Jeffrey Shuren, director of the FDA’s Center for Devices and Radiological Health, said Thursday in an agency news release.

“But, it is important that people understand that genetic risk is just one piece of the bigger puzzle. It does not mean they will or won’t ultimately develop a disease,” he added.

Along with genetics, many things can contribute to disease and illness, including lifestyle and environmental factors, the FDA said.

The newly approved tests work by isolating DNA from a saliva sample. The DNA is then tested for more than 500,000 genetic variants. The presence or absence of these variants is linked with higher risk for any one of 10 diseases and conditions.

Besides Parkinson’s or late-onset Alzheimer’s disease, they include: celiac disease; alpha-1 antitrypsin deficiency, which increases risk of lung and liver disease; a movement disorder called early onset primary dystonia; factor XI deficiency (hemophilia C), a blood clotting disorder; and Gaucher disease type 1, which causes liver and spleen enlargement and growth retardation.

The other three are glucose-6-phosphate dehydrogenase deficiency (or G6PD), a red blood cell condition; an iron overload disorder called hereditary hemochromatosis; and hereditary thrombophilia, a blood clot disorder.

Hoping to streamline approvals, the FDA plans to exempt additional 23andMe genetic health risk tests from its pre-market review. It said it may also exempt such tests from other companies that meet preliminary expectations.

By establishing special controls and a pre-market review exemption, “the FDA can provide a streamlined, flexible approach for tests using similar technologies to enter the market while the agency continues to help ensure that they provide accurate and reproducible results,” Shuren said.

The FDA said it does not plan exemptions for genetic health risk tests that function as diagnostic tests, which might be used for major treatment decisions. An example would be a genetic test for a BRCA mutation that may lead to removal of a woman’s breasts or ovaries in order to prevent cancer, the agency said.

Risks associated with the 23andMe genetic tests include false-positive findings -- meaning they wrongly indicate a key genetic variant in the test taker. Similarly, false-negative findings can occur where the results incorrectly indicate lack of a critical genetic variant.

Users of these tests should consult a health care professional with questions or concerns about results, the FDA said.