rs56411402

Cytochrome P450 3A (CYP3A) family of isoenzymes are responsible for metabolizing over half of prescribed drugs, thus determining absence of CYP3A expression is important for optimizing medical treatments. CYP3A5*4 is a rare variant in Chinese, Caucasians and Indians which may therefore not warrant screening for. At least one CYP3A5*1 allele is needed for expressing CYP3A5 protein, with normal levels up to half of CYP3A present in the liver. Allele variant *4 is identified by rs56411402 (14665A > G, p.Gln200Arg or Q200R) in exon 8. Note the reverse orientation; the most common form of this SNP is rs56411402(T), which is the same as '14665A' in publications. The rs56411402(C) allele defines the CYP3A5*4 variant, which is nonfunctional. Differential expression of cytochrome p450 enzymes in normal and tumor tissues from childhood rhabdomyosarcoma. Distribution of genetic polymorphisms of genes encoding drug metabolizing enzymes & drug transporters -- a review with Indian perspective. Genetic polymorphisms of drug-metabolizing phase I enzymes CYP2E1, CYP2A6 and CYP3A5 in South Indian population. Pharmacokinetics of midazolam and 1'-hydroxymidazolam in Chinese with different CYP3A5 genotypes. CYP3A5 variant allele frequencies in Dutch Caucasians. Genetic polymorphism of cytochrome P450 3A5 in Chinese. Sequence diversity in CYP3A promoters and characterization of the genetic basis of polymorphic CYP3A5 expression.