A study, reported on-line in Nature Genetics (January 16, 2005), found that 2 genetic mutations that are common in individuals of African descent are linked with a 50% reduction in low-density lipoprotein (LDL) cholesterol. Earlier studies involving mice showed that other mutations in the gene PCSK9 cause high cholesterol levels with raised LDL levels. To determine if there might be PCSK9 variations that have the opposite effect, researchers examined the deoxyribonucleic acid sequence of PCSK9 in 128 adults (half were African American) with low LDL levels.
The results of the study indicated that mutations in PCSK9 were shown in 2% of African Americans, but in <0.1% of European Americans. The findings also showed that carriers of the variant genes had significantly lower LDL and total cholesterol levels, compared with noncarriers. Based on the study's results, the researchers noted that the genetic mutations identified are "the most common sequence variants yet described to have large effects on plasma cholesterol levels."