title: CYP2D6 genetic polymorphism in South Indian populations.
abstract: This study aimed to determine the prevalence of genetic polymorphism in the CYP2D6 gene, which codes for the polymorphically expressed CYP2D6 drug-metabolizing enzyme. The common variants CYP2D6 *2, *3, *4, *5, *10, *14, and *17 were studied in the populations (n=447) of the four South Indian states namely Tamilnadu (TN), Kerala (Ker), Karnataka (Kar) and Andhra Pradesh (AP). Genetic polymorphisms were identified using polymerase chain reaction (PCR) and PCR-Restriction Fragment Length Polymorphism (PCR-RFLP) based methods. Differences in frequencies of CYP2D6 polymorphism between each South Indian state were statistically compared, and also the frequency of South Indian population as a whole in relation to other major populations. The CYP2D6*2 allele was the most frequent variant (34.8%), followed by the *10 allele (10.2%). The *4 and *5 alleles occurred at 7.3% and 1.9% respectively. The *3, *14 and *17 alleles were not detected in the study. The *1/*2, *1/*1 and *2/*2 genotypes were the most common CYP2D6 genotypes, representing 32.7%, 19.4% and 11.8% of the South Indian population. Genotypes that predict poor metabolizer phenotype i.e. *4/*4 and *4/*5 were found at 0.6% in South Indian population. The genetic composition at the CYP2D6 locus in South Indians is distinct from Caucasian, African and even other Asian (Chinese and Japanese) populations.
authors.affiliation: Pharmacogenomics Laboratory, Department of Pharmacology, JIPMER, India.
authors.forename: Amrithraj Theophilus
authors.initials: AT
authors.lastname: Naveen
authors.forename: Chandrasekaran
authors.initials: C
authors.lastname: Adithan
authors.forename: Sisy Sam
authors.initials: SS
authors.lastname: Soya
authors.forename: Nathalie
authors.initials: N
authors.lastname: Gerard
authors.forename: Rajagopal
authors.initials: R
authors.lastname: Krishnamoorthy
mesh_terms: D000483:Alleles; D001483:Base Sequence; D019389:Cytochrome P-450 CYP2D6 / Q000235:genetics*; D017931:DNA Primers; D006801:Humans; D007194:India; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length
chemical_list: D017931:DNA Primers; D019389:Cytochrome P-450 CYP2D6