Search for the molecular basis of ultra-rapid CYP2C9-catalysed metabolism: relationship between SNP IVS8-109A>T and the losartan metabolism phenotype in Swedes

Aim To search for a relationship between ultra-rapid metabolism catalysed by cytochrome P450 2C9 (CYP2C9) and its genotypes. Methods DNA from a Swedish ultra-rapid metaboliser patient [losartan metabolic ratio (MR) T) and CYP2C9 activity (χ 2 -test, p = 0.011) in the Swedes. Twenty Swedes with the lowest MR were compared with 20 Swedes with the highest MR, revealing a strong association ( p = 0.001) between SNP4 and higher MR. For homozygous SNP 1 (IVS1+83T>C), SNP 2 (IVS2+73T>C), and SNP 3 (IVS6+95A>G), no phenotype and genotype relationships were found, but the MR was generally higher among the Swedes compared to the Koreans (Mann–Whitney test, p