Angiotensin-converting enzyme gene polymorphism in patients with psoriatic arthritis.

To investigate the frequency of angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism genotypes in adults with psoriatic arthritis (PsA), a heterogeneous chronic disease with autoimmune pathology. ACE gene I/D polymorphism influences the plasma and tissue levels of ACE and has an involvement in inflammatory mechanism. The frequency of ACE gene I/D polymorphism genotypes was determined in 51 adults with PsA from Kuwait, and compared to that in 100 ethnically matched healthy controls using polymerase chain reaction. The distribution of ACE I/D polymorphism and allele frequencies in PsA patients were not significantly different from controls (P > 0.05). Further analyses of PsA patients showed that ACE I/D gene polymorphism was not associated with family history, clinical manifestations, and disease severity. However, the frequency of II genotype was significantly higher in patients with late disease onset than in those with early onset (25 vs. 3%; P = 0.04). No difference was found between the distribution of the ACE genotype in PsA patients and the general population in Kuwait. However, the presence of II genotype may confer susceptibility to the development of late onset PsA.