Familial Hypercholesterolemia Can be Missed on Some Gene Tests, Study Finds

According to a story from MedPage Today, a recent study has determined the familial hypercholesterolemia (FH) can often go undetected on genetic tests that rely on arrays. As an example, the researchers found that the 23andMe genetic test, which screens for a total of 24 known genetic variants associated with the condition, would have missed over 60 percent of patients. The risk of an inaccurate result appears to be higher in people of Black or Latin American ancestry. 

About Familial Hypercholesterolemia

Familial hypercholesterolemia is a condition of elevated, abnormally high levels of LDL cholesterol that is caused by a hereditary genetic mutation. The mutation that causes the condition affects the LDLR gene which normally codes for a protein that removes LDL from the bloodstream. The primary symptoms are elevated LDL cholesterol, deposits of cholesterol in certain areas of the body (eyelids, iris, and tendons of the arms and legs), and early onset cardiovascular issues, such as coronary artery disease, strokes, heart attack, and atherosclerosis. While once considered rare, it is likely that many people with the condition live undiagnosed. Treatment may include statins or other medications, liver transplant, or other surgical operations. The true prevalence of familial hypercholesterolemia remains unknown. To learn more about familial hypercholesterolemia, click here.

Study Findings

The scientists found that when using an array-based genetic test, the miss rate for the condition was 68.9 percent. Even in people that received proactive health screening, the miss rate was still 61.8 percent. These limited variant screens may mistakenly cause a person living with familial hypercholesterolemia to believe that they don’t have the condition. These array-based screenings would have missed 94 percent of Black and 85 percent of Latin American patients who were confirmed patients with pathogenic genetic variants.

“The reduced yield of limited-variant screening could result in a major health care disparity for groups already affected by social and medical disenfranchisement,” the researchers concluded.

The scientists recommend that physicians should seek a more thorough clinical genetic test if familial hypercholesterolemia is suspected and the result from an array-based test is negative. The findings from this study highlight a significant weakness in genetic testing for the condition as well as a major racial disparity in testing accuracy, which is likely the result of an overrepresentation of white populations in genetic databases.

Unfortunately, genetic testing for familial hypercholesterolemia is underutilized and as many as 90 percent of people with the condition will never be diagnosed. First-degree relatives of any confirmed patients should also be screened for the disease.

Check out the original study here.

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