To test whether genetic variation in the CYP system may influence the statin response, a promoter (A290G) and 2 nonsynonymous polymorphisms (F189S and M445T) in the CYP3A4 gene locus were examined in 340 hypercholesterolemic patients who were treated with atorvastatin 10 mg. The A-290G variant allele Was significantly associated with higher levels of post-treatment low-density lipoprotein cholesterol, whereas the M445T variant was associated with lower levels at low-density lipoprotein cholesterol before and after treatment. (C) 2003 by Excerpta Medica, Inc.