rs17244841

rs17244841, also known as SNP 12, is located in the HMG-CoA reductase HMGCR gene. The protein encoded by this gene is the target for drugs designed to inhibit its action, in order to lower cholesterol levels. SNPs in the HMGCR gene may affect how well such drugs (typically statins) work. In a study of ~1,500 patients treated with 40mg/d of pravastatin, rs17244841(A;T) heterozgyotes had a mean decrease in total cholesterol of –32.8 mg/dL (–0.85 mmol/L), while the mean change for rs17244841(A;A) homozygotes was –42.0 mg/dL (–1.09 mmol/L), a reduction in overall efficacy of 21.8% (absolute difference, 9.2 mg/dL, CI: 3.8-14.6 mg/dL, p=.001). The drop in total cholesterol was almost completely due to the decrease in LDL cholesterol, as there was no significant difference in the change in HDL cholesterol with pravastatin between genotypes. This SNP is in tight linkage (r 2 >0.90) with another, rs17238540, so practically speaking, they are equivalent to each other.