Juvenile idiopathic arthritis (JIA) is a non-common disease in children that can persist into adulthood. JIA is considered to be an auto-immune disease. Genetic factors play a role in the... Show moreJuvenile idiopathic arthritis (JIA) is a non-common disease in children that can persist into adulthood. JIA is considered to be an auto-immune disease. Genetic factors play a role in the pathogenesis. In a new cohort of JIA patients from North-West European descent genetic candidate gene association studies have been performed. In this cohort we have discovered new associations with the susceptibility of JIA and the genes/loci TRAF1/C5, 4q27, CD226 and CD28. These genes have already been associated with other auto-immune diseases and might be part of a shared common auto-immune susceptibility. Also genetic association with the course of disease has been studied, revealing an association of VTCN1 and the severity of JIA defined by the percentage of active disease in the first two years. VTCN1 encodes B7-H4 that is involved in the co-stimulation of T-cells and inhibits the immune-response. Until the precise role of VTCN1 will be clarified, the genetic association might be of use in predicting the course of disease and might be a lead point for new treatment. Show less
Rheumatoid Arthritis (RA) is a chronic autoimmune disease, affecting a ~1% of the population worldwide. Although its causes are largely unknown, a considerable heritable component approximating 50... Show moreRheumatoid Arthritis (RA) is a chronic autoimmune disease, affecting a ~1% of the population worldwide. Although its causes are largely unknown, a considerable heritable component approximating 50-60% has been described. The most prominent genetic association in RA is confined to the human leukocyte antigen (HLA) locus which has been known for ~30 years. The identification of RA-associated genes outside of the HLA region, however, had been a challenge. A few years ago, one such gene, protein tyrosine phosphatase, non-receptor type 22 (lymphoid), was identified in a large genetic-association study utilizing putative functional SNPs. The aim of this thesis was to take a candidate gene approach to identify risk factors involved in rheumatoid arthritis. It is divided into three parts in which part one is dedicated towards the identification of a novel risk factor for RA and autoimmunity. This region of the genome encompasses genes highly involved in the immune system, namely Tumour Necrosis Factor Receptor associated factor 1/Complement component 5 on chromosome 9q33. In the second part, we have investigated the role of an immunoregulatory cytokine interleukin 10 located on chromosome 1q32 and in part three we have investigated the role of additional genetic risk factors in RA. Show less
