Angiotensin-converting enzyme gene I/D polymorphism in Pakistani systemic lupus erythematosus patients
Angiotensin-converting enzyme (ACE) was first identified as a key component of the rennin-angiotensin system, as its main role is to process angiotensin I to angiotensin II and degrade bradykinin. Human ACE maps to chromosome 17q23 spans 21Kb, includes 26 exons and 25 introns. In humans, ID, DD, and II polymorphism is located in intron 16 of the angiotensin gene. The purpose of this study is to investigate the frequency of ACE gene insertion/deletion (I/D) polymorphism genotype in systemic lupus erythematosus (SLE) patients and to study the correlation between I/D polymorphism of the ACE gene and clinical manifestations of SLE. Sixty one (61) controls and 61 SLE patients were recruited from Punjab-Pakistan. Sixty one SLE patients and 61 control subjects were studied for ACE I/D polymorphism by using Triple primer method with nested polymerase chain reaction (PCR). The frequency of DD, ID and II genotypes was 54, 3 and 4% in SLE patients’ and 23, 32 and 6% in healthy controls, respectively. The frequency of DD allele in SLE patients with lupus nephritis is 100%, Sjogren’s syndrome 100%, Raynaud’s phenomenon 88.88%, and with rheumatoid arthritis it is 78.94%. The frequency of ID allele in SLE patients with Raynaud’s phenomenon is 5.55%, and with rheumatoid arthritis it is 10.52%. The frequency of II allele in SLE patients with Raynaud’s phenomenon 5.55%, rheumatoid arthritis is 10.52% but the important thing to note is that the frequency of II allele in SLE patients with vasculitis is 100%. This study was undertaken to determine whether DD, ID and II polymorphisms of Intron16 of the ACE gene is associated with SLE and whether the results support such an association. It can be concluded that lupus nephritis, Sjogren’s syndrome, Raynaud’s phenomenon, rheumatoid arthritis and vasculitis, which are common among Pakistani SLE patients, are related diseases and ACE gene is involved in lupus susceptibility.
Key words: Systemic lupus erythematosus, angiotensin converting enzyme I/D polymorphism, Sjogren’s syndrome, Raynaud’s phenomenon, rheumatoid arthritis, vasculitis.