Background Genetic variants have been identified associated with the susceptibility to Juvenile idiopathic arthritis (JIA). Little is known about the genetic determinants of disease severity and long-term outcomes.
Objectives This study aimed to assess the genetic determinants of poor outcome in Portuguese patients with JIA.
Methods Our study relied on Reuma.pt, the Rheumatic Diseases Portuguese Register, which includes patients with JIA receiving biological therapies and synthetic DMARDs. Subject and disease characteristics of patients with the diagnosis of JIA were collected prospectively and a blood sample for DNA analysis stored. Poor prognosis was defined as CHAQ/HAQ >0.75 at the last visit and/or the need for biological therapy. A previously selected panel of 31 single nucleotide polymorphisms (SNPs) was studied to verify if there was any association with poor prognosis.
Results 291 patients out of the 812 JIA patients registered in Reuma.pt, had a blood sample to perform the genetic analysis. From those, 267 had CHAQ/HAQ registered. The mean age was 19.9±11.3 years, 65% females. The mean age at JIA onset was 6.9±4.7 years. Of the 267 patients analyzed, 85 match our criteria of poor prognosis. In univariate analysis, including all disease categories of JIA, we found significant associations with poor prognosis for allele A of TNFA1P3/20 rs6920220, allele G of TRAF1/C5 rs3761847 and allele G of PTPN2 rs7234029. In multivariate models, the associations for TNFA1P3/20 rs6920220 (odds ratio =1.88 [95% CI 1.13-3.14]) and PTPN2 rs7234029 (OR 1.75 [1.03-3.00]) remained significant at the 5% level, while TRAF1/C5 rs3761847 (OR 1.53 [0.95-2.47]) was no longer significant.
Conclusions TNFA1P3/A20 and PTPN2 were associated with poor prognosis in Portuguese patients with JIA. These genes were also associated with susceptibility to JIA. Further studies in independent populations are needed to strengthen the knowledge in this field.
Disclosure of Interest None declared