Association Study of Genetic Variants in the 14q11 - 14q13 Proteasomal Genes Cluster with Juvenile Idiopathic Arthritis (JIA) in Latvian Population

Juvenile idiopathic arthritis (juvenile rheumatoid arthritis, JIA) is the most prevalent paediatric rheumatic diagnosis among children in many countries (Glass and Giannini, 1999). JIA is a clinically heterogeneous group of phenotypes that have in common chronic inflammatory synovitis in children under the age of 16 (Prahalad et al., 2001). Seven subtypes of JIA, based on the clinical characteristics at onset are distinguished; including the more frequent oligo, poly, psoriatic and systemic JIA variants (Petty at al., 2004). The genetic contributions to disease risk have been observed in many case/control studies (Glass and Giannini, 1999; Prahalad et al., 2001). A genome scan revealed linkage of JIA to the HLA region, additional evidence supporting linkage of JIA was observed at 1p36, 19p13, and 20q13 (Thompson et al., 2004). However, the low odds ratios for most individual “JIA risk alleles” suggest that gene–gene interactions, which are poorly described or understood at present, likely influence whether pathology develops (Glass and Giannini, 1999). This consideration encourages extension of the search for JIA candidate genes.