Juvenile Idiopathic Arthritis (JIA), afflicting ~1 in 10,000 North American Children, encompasses a highly heterogeneous group of chronic, immune-mediated joint disorders. Aside from causing severe pain, tissue damage, and physical immobility, chronic disease activity leads to permanent short stature and limb disfigurement. Similar to a number of other complex polygenic autoimmune diseases, there is a clear heritable component to JIA, but all known genetic risk factors explain less than 20% of disease heritability. The majority of this is attributable to variation across the Major Histocompatibility (MHC) locus, yet definitive high-resolution identification of MHC associations in JIA have not been conclusive. JIA is currently classified into seven clinical subtypes, based on a classification schema that has little research or clinical utility, since 10-50% of cases are classified as """"""""undifferentiated"""""""". Biological and molecular evidence based on the presence of serum autoantibodies and other molecular biomarkers of immunological defects suggest that the existing seven JIA subtypes could be grouped into two major classes-subtypes that represent either predominantly seropositive autoimmune (AID) diseases or seronegative autoinflammatory (AIF) diseases. Whether genetic risk factors differ for AID versus AIF-like JIA subtypes is unknown, especially since the traditional approach to genetic association studies is poorly powered to identify loci with subtype- specific effects in the presence of significant phenotypic heterogeneity. To test the hypothesis that distinct genetic risk factors underlie the clinically observed differences in AID versus AIF-like JIA subtypes and identify both shared and subtype-distinct genetic susceptibility loci, I propose to use a subtype-sensitive GWAS to identify JIA disease subtype-specific genetics associations, evaluate evidence for functional HLA associations that are distinct or shared across JIA subtypes, and test if the identified genetic associations can be used to predict disease susceptibility, distinguish patients who belong to AID versus AIF-like JIA classes, and reclassify patients currently defined as having undifferentiated disease. The analysis approach proposed here integrates genomic screening, disease modeling and prediction, and the use of expression and functional data resources to better understand the etiology of JIA. The successful completion of this work will likely yield novel biomolecular or pathway-based targets for the development of therapeutic agents for children with JIA and patients with other related rheumatological or immunological diseases.

Public Health Relevance

Juvenile Idiopathic Arthritis is a severe pediatric form of immune-mediate joint disease that can result in significant morbidity and life-long disability. While the etiology of JIA, similar to other complex autoimmune and inflammatory disorders that together affect nearly 10% of the United States population, is not well-understood, a strong genetic component has been demonstrated. My proposal aims to develop novel genome-wide analysis tools and applies these tools to the identification of genetic risk susceptibility factorsin JIA and other heterogeneous, complex hereditary disorders, which have the potential to yield promising disease-specific molecular and pharmacologic targets.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Individual Predoctoral NRSA for M.D./Ph.D. Fellowships (ADAMHA) (F30)
Project #
1F30AR066486-01
Application #
8717915
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Wang, Yan Z
Project Start
2014-06-01
Project End
2017-05-31
Budget Start
2014-06-01
Budget End
2015-05-31
Support Year
1
Fiscal Year
2014
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Pediatrics
Type
Schools of Medicine
DUNS #
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Li, Yun Rose; Kirk, Maura; Lin, Lilie (2016) Proton Therapy for Vaginal Reirradiation. Int J Part Ther 3:320-326
Li, Yun R; Li, Jin; Zhao, Sihai D et al. (2015) Meta-analysis of shared genetic architecture across ten pediatric autoimmune diseases. Nat Med 21:1018-27
Li, Yun R; Zhao, Sihai D; Li, Jin et al. (2015) Genetic sharing and heritability of paediatric age of onset autoimmune diseases. Nat Commun 6:8442
Li, Yun Rose; Matsunami, Hiroaki (2013) Unfolding the mystery of olfactory receptor gene expression. Dev Cell 27:128-129
Jamiolkowski, Ryan M; Guo, Lucie Y; Li, Yun Rose et al. (2012) Islet transplantation in type I diabetes mellitus. Yale J Biol Med 85:37-43
Interleukin-6 Receptor Mendelian Randomisation Analysis (IL6R MR) Consortium; Swerdlow, Daniel I; Holmes, Michael V et al. (2012) The interleukin-6 receptor as a target for prevention of coronary heart disease: a mendelian randomisation analysis. Lancet 379:1214-24
Li, Yun Rose; Matsunami, Hiroaki (2011) Activation state of the M3 muscarinic acetylcholine receptor modulates mammalian odorant receptor signaling. Sci Signal 4:ra1