Penn study shows a form of genetically elevated 'good' cholesterol may actually be bad

http://www.eurekalert.org/pub_releases/2016-03/uops-pss030416.php

Public Release: 10-Mar-2016
Penn study shows a form of genetically elevated 'good' cholesterol may actually be bad
Research has implications for better understanding the relationship between 'good' cholesterol function -- in addition to level -- and heart disease risk
University of Pennsylvania School of Medicine

The generally accepted medical maxim that elevated HDL cholesterol (HDL-C) is "good" has been overturned by a multi-center, international study, led by researchers from the Perelman School of Medicine at the University of Pennsylvania. They show that a certain genetic cause of increased HDL-C may actually be "bad," noting that a specific mutation in a gene which encodes a cell receptor protein that binds to HDL prevents the receptor from functioning. The mutation causes an increased risk of coronary heart disease even in the presence of elevated levels of HDL-C or "good" cholesterol.

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Previous research raised the possibility that HDL might not be quite as protective against heart disease as generally believed by cardiologists, especially after several clinical trials of HDL-raising drugs showed little or no effect. "The thinking about HDL has evolved recently to the concept that it may not directly protect against all heart disease," said senior author Daniel J. Rader, MD, chair of the department of Genetics. "Our results indicate that some causes of raised HDL actually increase risk for heart disease. This is the first demonstration of a genetic mutation that raises HDL but increases risk of heart disease."

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"The work demonstrates that the protective effects of HDL are more dependent upon how it functions than merely how much of it is present," Rader concluded. "We still have a lot to learn about the relationship between HDL function and heart disease risk."