Objectives: This study aims to investigate whether the protein tyrosine phosphatase non-receptor type 22 (PTPN22) C1858T gene polymorphism plays a role in the pathogenesis of familial Mediterranean fever (FMF) through T-lymphocyte activation. Patients and methods:We conducted a case-control study with 180 FMF patients (68 males, 112 females; mean age 38.2±1.6 years; range 16 to 81 years) and 184 healthy controls (86 males, 98 females; mean age 32.9±9.2 years; range 18 to 58 years). The PTPN22 C1858T polymorphism (rs2476601) was genotyped by polymerase chain reaction restriction fragment length polymorphism. In patients with FMF, clinical features, disease severity score, the frequencies of amyloidosis, positive family history, and Mediterranean fever gene mutations were determined. Results: The frequencies of heterozygous genotype (CT) were 4.5% in FMF patients and 2.8% in healthy controls, respectively. The frequencies of polymorphic homozygous genotypes (TT) were 0.5% in both FMF patients and healthy controls. There were no statistically significant differences in the frequencies of CT and TT genotypes between FMF patients and healthy controls (odds ratio: 1.65, 95% confidence interval: 0.53-5.14, p>0.05 for CT genotype). The frequencies of clinical features, sex, amyloidosis, positive family history, Mediterranean fever gene mutations, and disease severity score were not significantly different between the patients. Conclusion: The distribution of PTPN22 C1858T polymorphism did not reveal any association with FMF in a Turkish population.

Background PTPN22 gene plays role in TCR signaling. PTPN22 gene polymorphism has been recently found to be related to several autoimmune diseases. Objectives The aim of this study is to investigate the effect of PTPN22 gene polymorphisizm; which is related to several autoimmune disease; on the appereance and course of FMF which is also an autoinflammatory disease. Methods In this study, the study group and control group were composed of 180 FMF patient and 184 healthy adults, respectively. The patients with autoinflammatory, chronic inflammatory or autoimmune diseases other than familial mediterranean fever were excluded. A variant of PTPN22 gene, 1858 C/T, was examined by PCR-RFLP method in DNA samples taken from participants at study and control groups. Results The mean age of 180 patients was 38.2 (SD ±11.6) and the age distribution was 16-81. The numbers of females and males at study group were 112 (% 62.2) and 68 (% 37.8), respectively. The mean age of 184 healthy adult participiants at control group was 32.9 (SD ± 9.2) and age distribution was 18-58. The numbers of females and males at control group were 112 (% 62.2) and 68 (% 37.8), respectively. In the study group, PTPN22 gene polymorphism was studied in 177 of total 180 participants (product? couldn’t be obtained in blood samples of 3 patients). It was found that 168/177 (95%) were homozygotic (G/G polymorphism), 8/177 (%4.5) were heterozygotic (G/A polymorphism) and 1/177 (%0.5) was polymorphic homozygotic (A/A polymorphism). In the control group, PTPN22 gene polymorphism was studied in 180 of total 184 participants (product? couldn’t be obtained in blood samples of 4 patients). It was found that 174/180 (96,7%) were normal homozygotic (G/G polymorphism), 5/180 (%2.8) were heterozygotic (G/A polymorphism) and 1/180 (%0.5) was polymorphic homozygotic (A/A polymorphism). Conclusions We couldn’t find statistically significant datas between patients with FMF and healthy adults in terms of PTPN22 gene polymorphism. We also determined that PTPN22 gene polymorphism showed no statistically significant relationship with disease severity and clinical features of FMF. Even if it was not statistically significant, we determined that prolonged arthralgia and pericarditis was not present in the patients with PTPN22 G/A and A/A polymorphisms. More studies are needed in order to evaluate the relationship of PTPN22 gene polymorphism with FMF. References Onen F. Familial mediterranean Fever. Rheumatol Int. 2006 Apr; 26 (6): 489-96 Ben-Chetrit E, Levy M. Familial Mediterranean fever. Lancet. 1998 28;351:659-664 Wu J, Katrekar K, Honigberg LA, Smith AM, ConnMT, TangJ, Jeffrey D, Mortara K, Sampang J, Williams SR, Buggy J, Clark JM. Identification of substrates of human protein tyrosine phosphatase PTPN22. J Biol Chem 2006;281: 11002–11010. Torkel Vang, Ana V.Miletic, Nunzıo Bottını, Tomas Mustelın. Protein tyrosine phosphatase PTPN22 in human autoimmunity. Autoimmunity, September 2007; 40 (6): 453–461 Disclosure of Interest None Declared