Genes, Chromosomes, and Disease: From Simple Traits, to Complex Traits, to Personalized Medicine

4. Susceptibility genes and risk factors

Lipoprotein particles transport water-insoluble cholesterol and fats through the bloodstream. The particles formed vary in density with the most familiar being high-density lipoprotein (HDL) and low-density lipoprotein (LDL). HDL, also known as “good cholesterol,” carries cholesterol to the liver for processing, thus protecting against heart attack. LDL, or “bad cholesterol,” circulates in the bloodstream and builds up into plaques in the inner walls of arteries that feed the brain and the heart. These particles are made up of several different lipoproteins called apolipoproteins A through E. A different apolipoprotein (APO) gene encodes each of these proteins.

For years, most research on the apolipoproteins ...