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Health screening and genetic tests can detect more than 1 million adults in the United States who carry the gene for familial hypercholesterolemia, a common genetic disease that causes elevated low-density lipoprotein (LDL) cholesterol, known as “bad cholesterol,” which can lead to heartbeat. attack or death, according to a new study published today in Journal of the American Heart Associationpeer-reviewed journal of the American Heart Association with open access.

According to the American Heart Association, familial hypercholesterolemia is hereditary genetic disorder which affects how the body processes bad cholesterol. As a result, LDL levels in the blood remain very high; in severe cases the level can reach above 190 milligrams per deciliter (mg / dL) of blood in adults. The desired LDL level is less than 100 mg / dL. However, total blood cholesterol levels should be considered in the context of other known risk factors for cardiovascular disease.

It is estimated that 1 in 250 people in the United States may have at least one gene for familial hypercholesterolemia. Among people who have one gene for familial hypercholesterolemia, the average age is a first heart attack if the disease is not treated, is 50 years for men and 60 years for women, while the average age of the first heart attack in population as a whole is 66 years for men and 72 years for women. A much smaller number of people can inherit two familial hypercholesterolemia genes (one from each parent) and they have more severe complications including much higher levels of bad cholesterol and heart disease starting from childhood or adolescence.

“Currently, most people are not diagnosed with familial hypercholesterolemia until they are 50 years old. If a young adult is diagnosed with familial hypercholesterolemia, they are likely to benefit from earlier and more aggressive treatment to prevent heart attack and stroke,” – the study said. lead author Brandon K. Bellows, pharmacist, master, associate professor of medical science at Columbia University in New York.

The The American Heart Association recommends that in all adults 20 years of age and older, cholesterol and other traditional heart risk factors are checked every four to six years if the risk remains low. Screening for familial hypercholesterolemia is not standard and requires accurate collection of additional clinical information or diagnostic genetic testing. Genetic testing is available; however, this may not be affordable for many people if they are not covered by health insurance. And 2020 Scientific Statement of the American Heart Association suggests that genetic testing for cardiovascular disease should generally be performed for people who have a confirmed or suspected diagnosis of the disease, as well as for those in whose family a variant of the gene that causes the disease is known.

In this study, researchers estimated how many people with familial hypercholesterolemia could be identified if all adults were screened using clinical factors such as cholesterol levels and the presence of early heart disease in an individual or close family member (father, sibling, sister or child). both with and without genetic testing.

The researchers obtained clinical information and genetic test results for around 50,000 adults aged 40-69 from the UK Biobank, collected between 2006 and 2010. Based on this, they were able to assess the likelihood that each person has a familial genetic variant of hypercholesterolemia. on their clinical information. To evaluate genetic variants of familial hypercholesterolemia in the U.S. population that did not have genetic test results, the researchers applied the relationship observed in the UK Biobank to a data set of nearly 40,000 adults (ages 20 and older) from the National Health and Nutrition Survey. (NHANES).

The UK Biobank is a large biomedical database that includes genetic and medical information about half a million people living in the UK. NHANES is a representative sample of US adults, including people of different racial and ethnic backgrounds, collected from 1999-2000 to 2015-2016.

To evaluate the effectiveness of clinical criteria in U.S. data, the researchers used the Dutch Lipid Clinic Network criteria to classify people with definite or probable familial hypercholesterolemia based on a scoring system that combined a personal history of early heart disease; family history of early heart attack or chest pain (angina) in a brother, sister, parent or child; and high raw bad cholesterol levels, with higher scores for higher cholesterol.

Using this multi-step approach, the results are evaluated:

  • Clinical criteria alone revealed 3.7 cases of familial hypercholesterolemia per 1,000 adults surveyed, while only genetic testing revealed 3.8 cases of familial hypercholesterolemia per 1,000 adults surveyed.
  • Combining clinical criteria and genetic testing revealed 6.6 cases of familial hypercholesterolemia per 1,000 adults surveyed.
  • In young adults aged 20-39 years, 1.3 cases of familial hypercholesterolemia per 1,000 subjects were detected by clinical criteria alone, increasing to 4.2 per 1,000 when genetic testing was also included.

“We need to do more to support familial hypercholesterolemia screening programs,” Belauz said. Screening for familial hypercholesterolemia should include clinical factors and genetic testing. Individuals with high cholesterol or with a family member who has suffered a heart attack at a young age should undergo genetic testing for familial hypercholesterolemia and hypercholesterolemia. best ways to reduce wound risk heart attack or stroke.

The higher proportion of people identified through genetic testing added to clinical criteria suggests that many people with a genetic mutation may not exhibit a typical clinical picture at the time of screening. “This has been observed in other studies. Universal screening programs with genetic testing may be the best way to identify these individuals. However, it may be impractical, and thus targeted screening for certain groups, such as young adults, may allow early identification and treatment of familial hypercholesterolemia, ”Belauz said.

A limitation of the study is that the UK Biobank data set was a population of older people (aged 40-69 years), and most of whom identified themselves as white. Thus, the analysis of the UK Biobank data set cannot be generalized to different or young populations.

Researchers are conducting the following studies to answer questions about the most useful and cost-effective strategies for examining familial hypercholesterolemia, such as the best age to start the survey and whether there is a difference in the number of patients. heart seizures and strokes based on the screening method, such as universal screening against close family members with family hypercholesterolemia.

A new gene for familial high cholesterol

Additional information:
Estimated screening for heterozygous familial hypercholesterolemia with and without genetic testing in U.S. adults, Journal of the American Heart Association (2022). DOI: 10.1161 / JAHA.121.025192

Citation: Health screening, genetic tests can identify people at risk of premature heart disease (2022, May 18), obtained May 18, 2022 from people-premature. html

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