Association of insertion/deletion polymorphism of the angiotensin-converting enzyme gene with psoriasis

BACKGROUND: Genetic factors are likely to be of fundamental importance in the pathogenesis of psoriasis. There are reports concerning the induction or/and exacerbation of psoriasis by angiotensin-converting enzyme (ACE) inhibitors, which have been attributed to the ACE inhibitor-induced augmentation of kinin levels in skin. However, to the best of our knowledge there has been no molecular genetic study investigating whether ACE insertion/deletion (I/D) polymorphism may contribute to the genetic background in psoriasis. OBJECTIVES: To assess the role of ACE I/D polymorphism in psoriasis. METHODS: A group of 86 patients with psoriasis and 154 control subjects were analysed for ACE I/D polymorphism by polymerase chain reaction. RESULTS: The distribution of ACE I/D polymorphism and allele frequencies in psoriatic patients was not significantly different from controls. Further analyses of psoriasis patients showed that ACE I/D polymorphism was not associated with age at onset of disease, clinical type of psoriasis or gender. However, the frequency of the I allele was significantly higher in patients with a positive family history of psoriasis than in those with no family history (sporadic psoriasis) (48% vs. 32%; P =0.03). In addition, the I allele was found significantly more frequently in type I psoriasis patients (onset < 40 years and positive family history) than in type II psoriasis patients (onset >/= 40 years, no family history) (48% vs. 27%; P = 0.04). CONCLUSIONS: Our results suggest that the presence of the I allele may confer susceptibility to development of psoriasis in individuals from psoriatic families.