Monday, September 3, 2012
African Americans have higher blood levels of a protein associated with increased heart-disease risk than European Americans, despite higher "good" HDL cholesterol and lower "bad" triglyceride levels
This contradictory observation now may be explained, in part, by a genetic variant identified in the first large-scale, genome-wide association study of this protein involving 12,000 African American and Hispanic American women. Specifically, the researchers looked for genetic signposts associated with elevated levels of C-reactive protein, or CRP - a marker of inflammation that is linked with increased risk of heart disease, diabetes and some cancers. Most previous studies examining the genetic determinants of elevated CRP have focused on tens of thousands of white individuals of European descent. Since minorities - African Americans and Hispanic Americans in particular - tend to have higher CRP levels than other U.S. racial and ethnic groups, it's important to understand whether genetic factors might contribute to these differences. The researchers identified several genetic factors linked to CRP that are relatively specific to African Americans. They found a variation in TREM2, a family of genes on chromosome 6p21 that are expressed in white blood cells and appear to be important for regulating the degree of inflammation generated when white blood cells respond to infection or tissue injury. TREM genes were recognized relatively recently to be involved in inflammation and autoimmune disorders. The finding adds further support to the importance of this gene family in generating and regulating inflammatory responses.