title: Association of insertion/deletion polymorphism of the angiotensin-converting enzyme gene with angio-oedema accompanying chronic urticaria but not chronic urticaria without angio-oedema or the autologous serum skin test response.
abstract: BACKGROUND
  Chronic urticaria is defined as the daily or almost daily occurrence of weals for more than 6 weeks. The underlying pathophysiology is reported to be mast cell activation, with release of mast cell mediators, predominantly histamine. Substance P is a neuropeptide and has the capacity to provoke histamine release from skin mast cells. Angiotensin-converting enzyme (ACE), widely expressed in skin, is one of the major peptidase for the degradation of substance P. An insertion/deletion polymorphism (I/D) in the ACE gene has been reported to be related to the levels of enzyme.
  
  
  OBJECTIVE
  An increase in substance P levels due to a polymorphism in ACE gene might be related to the pathology. Thus, we aimed to investigate whether there is an association between ACE I/D polymorphism and chronic ordinary urticaria.
  
  
  METHODS
  Ninety-five patients with chronic ordinary urticaria were recruited and divided into two groups according to autologous serum skin test status and accompanying angio-oedema. One hundred and sixty-one healthy subjects were enrolled as control group. All participants were genotyped for I/D polymorphism in intron 16 of the ACE gene by polymerase chain reaction.
  
  
  RESULTS
  A statistically significant association was not found between ACE I/D polymorphism and chronic ordinary urticaria. Further analyses of chronic ordinary urticaria patients showed that ACE I/D polymorphism was not associated with autologous serum skin test status of patients. However, the frequencies of II genotype and I allele were statistically significantly higher in chronic ordinary urticaria patients with accompanying angio-oedema with regard to angio-oedema-negative patients (II genotype: 24% vs. 9%, P = 0.0002; I allele: 58% vs. 27%, P = 0.0001) and control group (II genotype: 24% vs. 19%, P = 0.01; I allele: 58% vs. 41%, P = 0.03).
  
  
  CONCLUSIONS
  The results of this study suggest no evidence of an association between ACE I/D polymorphism and risk of developing chronic ordinary urticaria. However, it can be a contributing factor to susceptibility of angio-oedema in chronic ordinary urticaria.
authors.affiliation: Department of Dermatology, Medical Faculty, Gaziantep University, Gaziantep, Turkey. cenkakcali@yahoo.com
authors.forename: C
authors.initials: C
authors.lastname: Akcali
authors.forename: M
authors.initials: M
authors.lastname: Ozkur
authors.forename: Z
authors.initials: Z
authors.lastname: Erbagci
authors.forename: N
authors.initials: N
authors.lastname: Benlier
authors.forename: A S
authors.initials: AS
authors.lastname: Aynacioglu
mesh_terms: D000328:Adult; D000483:Alleles; D000799:Angioedema / Q000150:complications / Q000235:genetics* / Q000378:metabolism; D016022:Case-Control Studies; D002908:Chronic Disease; D004198:Disease Susceptibility; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D007703:Peptidyl-Dipeptidase A / Q000235:genetics* / Q000378:metabolism; D011110:Polymorphism, Genetic / Q000235:genetics*; D013373:Substance P / Q000378:metabolism; D014581:Urticaria / Q000150:complications / Q000235:genetics* / Q000378:metabolism
chemical_list: D013373:Substance P; D007703:Peptidyl-Dipeptidase A