A novel CYP1A1 gene polymorphism in African-Americans.

A new Msp1 RFLP in the CYP1A1 gene has been found in genomic DNA from African-Americans. The polymorphism results from a single A-T to G-C transition in the 3' noncoding region approximately 300 bp upstream from the polyadenylation site. This mutation leads to cleavage of the normal 2.3 kb MspI restriction fragment into 1.3 and 1.0 kb fragments. The heterozygous mutation has been seen in 8 of 47 African-Americans, but was not detected in 191 Caucasians or 30 Asians. No linkage was observed with either of the two previously described polymorphisms in this gene.