genetic testing for familial hypercholesterolemia

23andMe Genetic Health Risk Report on FH

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Today, 23andMe announced a new Genetic Health Risk Report for Familial Hypercholesterolemia.

Now, individuals who are 23andMe Health+ Ancestry service customers will be alerted if they have one of 24 of the more common gene variants for Familial Hypercholesterolemia (FH) that can be analyzed. Since 90% of individuals with FH are undiagnosed, this new report could alert more people of their heart disease risk who have an FH mutation.

Individuals with FH are at an up to 10 times the risk of early heart disease versus individuals that do not have FH. This risk can be greatly reduced when FH is identified and treated early. Therefore, the 23andMe report could have a positive impact on individuals (and potentially their families) should those that are alerted seek proper medical attention due to this service.

However, this new report does have significant limitations. There are over 2,000 known genetic variants that can cause FH, and only 24 of those variants will be analyzed in this new report. 23andMe’s report looks at some of the more common FH variants in people of European ancestry.

The vast majority of people will receive a report saying that no FH causal variants were detected (a so called “negative” test). These individuals can still have FH. Due to the genotyping technology used, many FH mutations will not be found. Therefore, individuals who receive report indicating that no FH causal variants were identified but who have high LDL-cholesterol (over 190 mg/dl) and a family history of early heart disease should still see a specialist to be screened for FH.

If you or someone you know has been clinically diagnosed with FH and receive a negative test result through 23andMe, you could still have FH. Given the small number of variants tested, it is possible that the 23andMe test did not test for the variant you have.

It is also important to remember that even using more comprehensive genetic testing strategies ordered by a physician will not always identify a causal variant. Up to 30% of individuals with clinically diagnosed FH will not have a defined mutation using clinical gene testing.

If you have been diagnosed with FH and are considering genetic testing, the FH Foundation recommends evaluating clinical genetic testing services that fully analyze the three known genes to cause FH (LDLR, APOB and PCSK9). More information on what to look for can be found in our online guide.

We believe this report is a positive initial step for many individuals to become aware of FH. For the individuals that are identified by the 23andMe testing and act on it, this information may prevent heart attacks or even death. Therefore, while we know that genetic testing alone is not enough to find the over million individuals that are undiagnosed, it is nevertheless important to help these individuals navigate this new genetic information.

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