title: Allele and genotype frequency of a genetic variant in ataxia telangiectasia mutated gene affecting glycemic response to metformin in South Indian population.
abstract: Allele and genotype frequency of a genetic variant in ATM gene affecting glycemic response to metformin in South Indian population.
  
  
  BACKGROUND
  The novel polymorphism in ATM gene (rs11212617), which is implicated to have association with metformin response, exhibits inter-ethnic variability in the allele and genotype frequency distribution.
  
  
  OBJECTIVE
  The objective of the present study is to establish the allele and genotype frequency of rs11212617 single nucleotide polymorphism in ATM gene, in South Indian population and to find if this variant has any role in the etiology of type 2 diabetes mellitus.
  
  
  METHODS
  The study was performed in 2 cohorts of populations, 112 healthy volunteers and 118 type 2 diabetes mellitus patients. Genomic deoxyribonucleic acid (DNA) was extracted from peripheral blood leucocytes by phenol-chloroform method and genotyping was performed by real-time polymerase chain reaction using TaqMan assay.
  
  
  RESULTS
  In South Indian population, the frequency of major A allele was 0.65 and the minor C allele was 0.35. AA and CC are the homozygous genotypes with frequency of 0.39 and 0.09 respectively. The frequency of heterozygous genotype AC (0.52) was found to be higher than the homozygotes. There was no significant difference in the frequency distribution in the diabetic population, which implies that this variant does not have any causative role in the disease etiology. The frequency distributions were found to be significantly different from the distributions in other ethnic populations such as Caucasians, Chinese, Japanese and Africans. But there was no significant difference when compared with the Gujarati Indians of Houston.
  
  
  CONCLUSIONS
  The frequency distribution of this novel variant in South Indian population forms a framework for further gene disease association studies to establish the association of this variant with metformin response. Our study could not find any association of this variant with respect to the disease etiology.
authors.affiliation: Department of Pharmacology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India.
authors.forename: Saranya
authors.initials: S
authors.lastname: Vilvanathan
authors.affiliation: Department of Pharmacology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India.
authors.forename: Umamaheswaran
authors.initials: U
authors.lastname: Gurusamy
authors.affiliation: Department of Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India.
authors.forename: V
authors.initials: V
authors.lastname: Mukta
authors.affiliation: Department of Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India.
authors.forename: Ashok Kumar
authors.initials: AK
authors.lastname: Das
authors.affiliation: Department of Pharmacology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India.
authors.forename: Adithan
authors.initials: A
authors.lastname: Chandrasekaran
keywords: Ataxia telangiectasia mutated gene; diabetes; metformin