Review

A comprehensive review of the genetics of juvenile idiopathic arthritis

Sampath Prahalad¹ and David N Glass²

¹  Assistant Professor of Pediatrics, Division of Immunology and Rheumatology, Department of Pediatrics, University of Utah School of Medicine, P.O Box 581289 Salt Lake City, UT 84158-1289, USA

²  Professor of Pediatrics, University of Cincinnati College of Medicine, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., MLC 7030, Cincinnati, OH 45229, USA

author email corresponding author email

Pediatric Rheumatology 2008, 6:11doi:10.1186/1546-0096-6-11

Published:	21 July 2008

Abstract

Juvenile idiopathic arthritis (JIA) is the most common chronic arthropathy of childhood which is believed to be influenced by both genetic and environmental factors. The progress in identifying genes underlying JIA susceptibility using candidate gene association studies has been slow. Several associations between JIA and variants in the genes encoding the human leukocyte antigens (HLA) have been confirmed and replicated in independent cohorts. However it is clear that genetic variants outside the HLA also influence susceptibility to JIA. While a large number of non-HLA candidate genes have been tested for associations, only a handful of reported associations such as PTPN22 have been validated. In this review we discuss the principles behind genetic studies of complex traits like JIA, and comprehensively catalogue non-HLA candidate-gene association studies performed in JIA to date and review several validated associations. Most candidate gene studies are underpowered and do not detect associations, and those that do are often not replicated. We also discuss the principles behind genome-wide association studies and discuss possible implications for identifying genes underlying JIA. Finally we discuss several genetic variants underlying multiple clinically distinct autoimmune phenotypes.