title: Glutathione S-transferase M1 and T1 null genotype distribution in South Indians.
abstract: OBJECTIVE
  To investigate the distribution of the homozygous null genotypes of GSTM1 and GSTT1 in the South Indian population.
  
  
  METHODS
  Five hundred and seventeen unrelated natives of the South Indian states of Tamilnadu and Pondicherry (n=170), Kerala (n=122), Karnataka (n=110) and Andhra Pradesh (n=115) were analyzed for homozygous deletions of GSTM1 and GSTT1. A multiplex polymerase chain reaction method simultaneously detected both GSTM1 and GSTT1 homozygous null genotypes. The observed frequencies from the four groups were compared statistically with each other and the combined frequencies were compared with frequencies of other major populations previously reported in the literature.
  
  
  RESULTS
  In South India, 30.4% (95% CI 26.4-34.3) lacked the GSTM1 gene, 16.8% (13.6-20.1) lacked the GSTT1 gene and 4.6% (3.0-6.8) lacked both the GSTM1 and GSTT1 genes. The highest frequency of GSTM1 null was observed in Karnataka (36.4%, 27.4-45.4), while Andhra Pradesh had the lowest frequency of the GSTM1 and GSTT1 combined double-null genotypes (1.7%, 0.21-6.2).
  
  
  CONCLUSIONS
  The prevalence of the GSTM1 null genotype differed within India. The frequency of GSTM1 null in South Indians was significantly lower than that in Caucasians. The frequencies of both GSTM1 and GSTT1 null genotypes in South Indians were significantly lower than in the Japanese.
authors.affiliation: Pharmacogenomics Laboratory, Department of Pharmacology, JIPMER, 605 006 Pondicherry, India.
authors.forename: A T
authors.initials: AT
authors.lastname: Naveen
authors.forename: C
authors.initials: C
authors.lastname: Adithan
authors.forename: N
authors.initials: N
authors.lastname: Padmaja
authors.forename: C H
authors.initials: CH
authors.lastname: Shashindran
authors.forename: B K
authors.initials: BK
authors.lastname: Abraham
authors.forename: K
authors.initials: K
authors.lastname: Satyanarayanamoorthy
authors.forename: P
authors.initials: P
authors.lastname: Anitha
authors.forename: N
authors.initials: N
authors.lastname: Gerard
authors.forename: R
authors.initials: R
authors.lastname: Krishnamoorthy
mesh_terms: D000328:Adult; D005260:Female; D017353:Gene Deletion; D005787:Gene Frequency; D005838:Genotype; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D005982:Glutathione Transferase; C413545:glutathione S-transferase T1