NCIt definition : Human CYP2C19*9 allele is located within 10q24.1-q24.3 and is approximately 90 kb
in length. This allele, a variant form of the CYP2C19 wild-type allele, encodes cytochrome
P450 2C19*9 protein. The CYP2C19*9 allele exhibits a clinically-relevant SNP (c.431G
A) in exon 3 that results in a R144H coding change. This alteration in protein sequence
decreases the enzymatic activity of the cytochrome P450 2C19*9 protein.;