NCIt definition : Human CYP2C9*18 allele is located within 10q24 and is approximately 33 kb in length.
This allele, a variant form of the CYP2C9 wild-type allele, encodes cytochrome P450
2C9*18 protein. The CYP2C9*18 allele exhibits a clinically-relevant SNP (c.1190A C)
in exon 8 that results in a D397A coding change. This alteration in protein sequence
decreases the in vivo enzymatic activity of the cytochrome P450 2C9*18 protein.;