Correlation between angiotensin-converting-enzyme 2 gene polymorphisms and systemic sclerosis

Systemic sclerosis (SSc) is a disease with cardiovascular impairment and polymorphisms of the gene coding of angiotensin-converting-enzyme 2 (ACE2) may account for its development. Three single nucleotide polymorphisms of ACE2 (C>G rs879922, G>A rs2285666 and A>G rs1978124) were found to increase the risk for development of arterial hypertension (AH) and cardiovascular (CVS) diseases in different ethnicities. We investigated associations of polymorphisms rs879922, rs2285666 and rs1978124 with the development of SSc.

Genomic DNA was isolated from whole blood. Restriction-fragment-length polymorphism was used for genotyping of rs1978124, while detection of rs879922 and rs2285666 was based on TaqMan SNP Genotyping Assay. Serum level of ACE2 was assayed with commercially available ELISA test.

81 SSc patients (60 women, 21 men) were enrolled. Allele C of rs879922 polymorphism was associated with significantly greater risk for development of AH (OR=2.5, p=0.018), but less frequent joint involvement. A strong tendency to earlier onset of Raynaud's phenomenon and SSc was seen in carriers of allele A of rs2285666 polymorphism. They had lower risk for development of any CVS disease (RR=0.4, p=0.051) and tendency to less frequent gastrointestinal involvement. Women with genotype AG of rs1978124 polymorphism had significantly more frequent digital tip ulcers and lower serum level of ACE2.

Polymorphisms of ACE2 may account for the development of AH and CVS disorders in SSc patients. Strong tendencies to more frequent occurrence of disease specific characteristics distinct to macrovascular involvement will require further studies evaluating significance of ACE2 polymorphisms in SSc.