Objective: It has recently been reported that some autoimmune diseases seem to be associated with a functional polymorphism in PTPN22, a gene which encodes a phosphatase known to be important in T-cell signaling. The aim of our study was to check for the prevalence of the PTPN22 R620W polymorphism in patients with systemic sclerosis.
Methods: DNA samples from 54 systemic sclerosis patients and 55 healthy controls were obtained from peripheral blood and genotyping was performed by means of a restriction fragment length polymorphism analysis of PCR products (RFLP-PCR).
Results: Allele frequency for the T allele was slightly higher in the patients group (0.074 versus 0.055). Eight out of the 54 systemic sclerosis patients (14.8 %) were heterozygous for this single nucleotide polymorphism whereas the CT genotype was found in 6 out of the 55 controls (10.9%). Nevertheless, the difference did not reach statistical significance (p = 0.542). Neither certain antibodies linked to systemic sclerosis (anti-centromere and anti-topoisomerase I antibodies) nor any particular clinical involvement were associated with the polymorphism.
Conclusion: This particular single nucleotide polymorphism of PTPN22 does not seem to be associated with systemic sclerosis.