Study Locates Cholesterol Genes; Finds Surprises About Good, Bad Cholesterol

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Study Locates Cholesterol Genes; Finds Surprises About Good, Bad

Cholesterol

http://www.medicalnewstoday.com/articles/93851.php

An international study of 20,000 people found seven new genes that

influence blood cholesterol levels, a major factor in heart disease,

and confirmed 11 other genes previously thought to influence

cholesterol.

The international study led by researchers from the University of

Michigan School of Public Health set out to identify or confirm

genetic variants that influence lipid levels, and secondly, to see

if those variants were linked to the decreased or increased risk of

heart disease. The findings were published online in the journal

Nature Genetics on Jan. 13.

The results may lead the medical community to rethink the role of

HDL (good cholesterol) and LDL (bad cholesterol) in heart disease,

said Goncalo Abecasis, associate professor in the U-M School of

Public Health. Abecasis co-directed the study with Mohlke,

assistant professor of genetics at the University of North Carolina

at Chapel Hill School of Medicine.

" It was surprising that while genetic variants that increase your

bad cholesterol are also associated with increased risk of heart

disease, we did not find that variants influencing your good

cholesterol were associated with decreased risk of coronary artery

disease. Perhaps that result will lead us to reexamine the roles of

good and bad cholesterol in susceptibility to heart disease, "

Abecasis said.

Coronary artery disease, a condition where plaque accumulates on the

walls of coronary arteries, is the most common type of heart disease

and a leading cause of death in industrialized countries. The type

and amount of cholesterol and other lipids in the bloodstream

contribute to the risk of coronary artery disease, which can cause

heart attack, stroke, angina and other heart conditions. Both

genetic and environmental factors influence a person's cholesterol

and blood lipid levels.

" Finding new gene regions associated with cholesterol levels may

bring us one step closer to developing better treatments, said

Cristen Willer, co-first author and a research fellow in the

Department of Biostatistics. " Nearly all of the gene regions that we

found to be involved in higher LDL levels were also involved in

coronary artery disease risk. This is a remarkable result and

suggests that new drug therapies that target the genes in these

regions will also help prevent coronary artery disease and allow

people to live longer and healthier lives. " Serena Sanna, who worked

on the paper as a post-doctoral student in Abecasis' group and who

is now at the National Research Council di Cagliari in Italy, is co-

first author.

Of the seven new variants, two influenced HDL, one influenced LDL,

and three influenced triglycerides, which are found in fat and in

the bloodstream and like LDL, are associated with increased risk of

heart disease. One variant influenced triglycerides and LDL.

Scientists initially examined 2 million genetic variants in 8,800

individuals and ended up focusing on a total of 25 genetic variants

on 18 genes. Altogether the variations reported are responsible for

less than a quarter of the genetic contributions to lipid levels.

The completion of the map of human genetic variation, or HapMap, has

fueled a surge in this type of genome-wide association study, with

most of the growth coming in the past 10 months. Researchers around

the globe have now associated more than 60 common DNA variants with

the risk of more than 20 common diseases or related traits.