Human CYP3A5*6 allele is located in the vicinity of 7q21.1 and is approximately 32 kb in length. This allele, a variant form of the human CYP3A5 wild-type allele, encodes cytochrome P450 3A5*6 protein. The CYP3A5*6 allele exhibits a clinically-relevant SNP (g.14690G>A), resulting in deletion of exon 7 from the splice variant, a frame shift and premature stop at 184 amino acids. Truncation of the cytochrome P450 3A5*6 protein causes complete loss of enzymatic activity. [ ]