title: Leptin gene tetranucleotide repeat polymorphism in obese individuals in Egypt.
abstract: BACKGROUND
  Leptin is a peptide hormone secreted by the adipose tissue. Genetic mutations of the leptin gene were reported to cause severe obesity.
  
  
  OBJECTIVE
  This study was undertaken to investigate the association of the polymorphic tetranucleotide repeat locus 3' UTR of leptin gene with obesity in Egyptian cases.
  
  
  METHODS
  This study has included 120 subjects affected with obesity 57 of them were consistent with the diagnosis of metabolic syndrome (MS) while the rest (63) had simple obesity. These cases were compared to 83 normal weight healthy controls. All participants were subjected to an estimation of their body mass index (BMI), waist hip ratio (WHR), serum as well as characterization of leptin gene tetranucleotide repeat (TTTC)n polymorphism by PCR technique.
  
  
  RESULTS
  Thirteen different alleles were identified in all cases of obesity versus only 5 alleles in normal controls. The most frequent allele was the 154 bp allele (57.5% in all cases of obesity vs. 92.2% in controls). Total cases with obesity showed a significantly higher carriage rate of class II alleles (I/II + II/II genotypes) compared to healthy controls (48.3% vs. 6.0%, OR=14.6, 95% CI=5.5-38.6, p=<0.0001). This was more apparent in the group with simple obesity (52.3% vs. 6.0%, OR=17.2, 95% CI=6.1-48.1, p=<0.0001) than in MS cases (43.9 % vs. 6.0 %, OR =12.19, 95% CI=4.9-30.4, p=< 0.0001). Interestingly, cases with MS did not differ from those with simple obesity regarding their class I or II allele frequencies (p> 0.05). Although serum lipids were significantly higher in obese cases compared to controls, no difference was found among obese cases with different leptin gene class genotypes (p> 0.05).
  
  
  CONCLUSIONS
  Tetranucleotide repeat (TTTC)n polymorphism in the 3' UTR of the human leptin gene was associated with obesity in Egyptian obese cases showing higher class II allele carriage rate. However, the lipoprotein levels were not affected by this polymorphism.
authors.affiliation: Genetics Unit, Faculty of Medicine, Mansoura University.
authors.forename: Rizk
authors.initials: R
authors.lastname: Elbaz
authors.affiliation: Zoology Department, Faculty of Science, Tanta University.
authors.forename: Nahed
authors.initials: N
authors.lastname: Dawood
authors.affiliation: Zoology Department, Faculty of Science, Tanta University.
authors.forename: Hala
authors.initials: H
authors.lastname: Mostafa
authors.affiliation: Zoology Department, Faculty of Science, Tanta University.
authors.forename: Somaia
authors.initials: S
authors.lastname: Zaki
authors.affiliation: Assistant Professor of Medicine, Mansoura University.
authors.forename: Alaa
authors.initials: A
authors.lastname: Wafa
authors.affiliation: Professor of Pediatrics, Faculty of Medicine, Mansoura University.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Settin
keywords: Gene polymorphism; Leptin gene; Metabolic syndrome; Obesity