title: The G1057D polymorphism of IRS-2 gene is not associated with type 2 diabetes and obese patients among ethnic groups in Tunisian population.
abstract: BACKGROUND
  Type 2 of diabetes is the most common metabolic disorder and results from the interaction between genetic and environmental factors. Insulin receptor substrate-2 (IRS-2), one of the major substrates of the insulin receptor, has a crucial role in insulin signalling and in beta cell development and survival. While several polymorphisms have been identified in the IRS-2 gene, the association of the Gly1057Asp polymorphism with type 2 diabetes has been studied in European and Chinese populations, but the results have been inconsistent.
  
  
  OBJECTIVE
  The aim of this study was to investigate the association of Gly1057Asp polymorphism in insulin receptor substrate-2 (IRS-2) gene among patients with type 2 diabetes in well defined ethnic groups from Djerba Island in Southeastern Tunisia.
  
  
  METHODS
  The studied population (172 Arabs and 100 Berbers) includes 162 patients with type 2 diabetes and 110 healthy controls. BMI was calculated for each subject. The subjects were unrelated and randomly selected Arabs and Berbers were equally distributed between controls and diabetics. The G1057D polymorphism of the IRS-2 gene was genotyped using PCR-RFLP assay.
  
  
  RESULTS
  This case/control study indicated that frequency of the IRS-2 Gly1057Asp polymorphism was not significantly different between the healthy controls and type 2 diabetic groups, neither between healthy nor obese subjects, in both ethnic groups. Moreover, this polymorphism is present at a lower frequency in Djerbian than in neighbouring European populations.
  
  
  CONCLUSIONS
  These results strongly argue against a major role of the Gly1057Asp IRS-2 polymorphism in the pathogenesis of type 2 diabetes in Djerbian subjects.
authors.affiliation: Laboratory of Genetics, Immunology and Human Pathologies, Faculty of Sciences of Tunis, El Manar II University, 2092 Tunis, Tunisia. Thourbar@yahoo.fr
authors.forename: Thouraya Baroudi
authors.initials: TB
authors.lastname: Ouederni
authors.forename: Jose
authors.initials: J
authors.lastname: Sanchez-Corona
authors.forename: Silvia E
authors.initials: SE
authors.lastname: Flores Martinez
authors.forename: Hedi
authors.initials: H
authors.lastname: Ben Maiz
authors.forename: Hajer Aounallah
authors.initials: HA
authors.lastname: Skhiri
authors.forename: Hafaoua Kammoun
authors.initials: HK
authors.lastname: Abid
authors.forename: Amel
authors.initials: A
authors.lastname: Benammar-Elgaaied