Not a black and white question

摘要

Last month researchers from the University of Texas and the University of Mississippi Medical Centre published a paper in the New England Journal of Medicine. They had studied three versions (or alleles, as they are known) of a gene called PCSK9. This gene helps clear the blood of low-density lipoprotein (LDL), one of the chemical packages used to transport cholesterol around the body. Raised levels of LDL are associated with heart disease. The effect of all three types of PCSK9 studied by Jonathan Cohen and his colleagues was to lower the LDL in a person's bloodstream by between 15% and 28%, and coronary heart disease by between 47% and 88%, compared with people with more common alleles of the gene.