A rare genetic abnormality found in people in an insular Amish community protects them from heart disease, a discovery that could lead to new drugs to prevent heart ailments, U.S. researchers said on Thursday.
About 5 percent of Old Order Amish people in Pennsylvania's Lancaster County have only one working copy rather than the normal two of a gene that makes a protein that slows the breakdown of triglycerides, a type of fat that circulates in the blood, the researchers wrote in the journal Science.
"People who have the mutation all have low triglycerides," said Toni Pollin of the University of Maryland School of Medicine in Baltimore, who led the study.
"This gives us clues that ultimately could develop future treatments."
Triglycerides naturally disappear more quickly in these people than in people without this gene mutation.
High triglyceride levels, often due to a high-fat diet, can contribute to hardening and narrowing of the arteries, raising the risk of heart attack, heart disease and stroke.
New drugs might target this gene, called APOC3, to decrease the amount of the protein it produces, Pollin said in an interview.
Pollin and colleagues looked at the genes of about 800 Amish people, finding that about one in 20 had the mutation, and they also had lower triglycerides and less risk of cardiovascular disease.
They also had high levels of HDL-cholesterol, the so-called good cholesterol, and low levels of LDL-cholesterol, the so-called bad cholesterol.
Having only one working copy of APOC3 left people with half the normal level of the protein the gene makes.
"The Old Order Amish are ideal for genetic research because they are a genetically homogenous people who trace their ancestry back 14 generations to a small group that came to Pennsylvania from Europe in the mid-1700s," Dr. Alan Shuldiner, one of the researchers, said in a statement.
Since then, the devoutly Christian Amish have largely kept to themselves in close-knit farming communities, typically marrying other Amish people. Amish communities also are found in Ohio, Indiana and elsewhere.
The researchers believe this genetic mutation was introduced into the Lancaster Amish population by a person born in the mid-1700s, and the trait seems to be very rare or completely absent in the general population.