Table of Contents
ISRN Dermatology
Volume 2013, Article ID 203941, 4 pages
http://dx.doi.org/10.1155/2013/203941
Research Article

The Role of 39 Psoriasis Risk Variants on Age of Psoriasis Onset

1Department of Dermatology, University of California San Francisco, 2340 Sutter Street, P.O. Box 0808, San Francisco, CA 94143-0808, USA
2Department of Gastroenterology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Institute of Digestive Diseases, Shanghai 200001, China
3University of California Irvine School of Medicine, Irvine, CA 92697, USA
4University of Utah School of Medicine, Salt Lake City, UT 84132, USA
5Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
6Chicago College of Osteopathic Medicine, Downers Grove, IL 60515, USA

Received 16 July 2013; Accepted 29 August 2013

Academic Editors: B. Amichai, G. Chodorowska, C. Ferrándiz, and A. Tosca

Copyright © 2013 Yingchang Lu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Recent genome-wide association studies (GWAS) have identified multiple genetic risk factors for psoriasis, but data on their association with age of onset have been marginally explored. The goal of this study was to evaluate known risk alleles of psoriasis for association with age of psoriasis onset in three well-defined case-only cohorts totaling 1,498 psoriasis patients. We selected 39 genetic variants from psoriasis GWAS and tested these variants for association with age of psoriasis onset in a meta-analysis. We found that rs10484554 and rs12191877 near HLA-C and rs17716942 near IFIH1 were associated with age of psoriasis onset with false discovery rate < 0.05. The association between rs17716942 and age of onset was not replicated in a fourth independent cohort of 489 patients ( ). The imputed HLA-C*06:02 allele demonstrated a much stronger association with age of psoriasis onset than rs10484554 and rs12191877. We conclude that despite the discovery of numerous psoriasis risk alleles, HLA-C*06:02 still plays the most important role in determining the age of onset of psoriasis. Larger studies are needed to evaluate the contribution of other risk alleles, including IFIH1, to age of psoriasis onset.