Detection of three genetic polymorphisms in the 5 '-flanking region and intron 1 of human CYP1A2 in the Japanese population

Interindividual variability of the activity of CYP1A2 may be expected to af fect cancer susceptibility, since the enzyme is capable of activating sever al carcinogens. In the present study, we found three new polymorphisms in t he 5'-flanking region (CYP1A2/B) and intron 1 (CYP1A2/C and CYP1A2/D) of CY P1A2 in Japanese by using polymerase chain reaction-single strand conformat ion polymorphism. We developed methods to detect these polymorphisms by pol ymerase chain reaction-restriction fragment length polymorphism and perform ed a population study (159 subjects) to estimate the frequencies of the all eles, The frequencies of the CYP1A2/A (adenine), CYP1A2/B (thymine-deleted) , CYP1A2/C (guanine) and CYP1A2/D (adenine) variants were 21.1, 42.0, 8.2 a nd 61.3%, respectively. The results of family study supported the idea that these CYP1A2 genotypes are inherited with an autosomal codominant transmis sion.