Five regulatory genes detected by matching signatures of eQTL and GWAS in psoriasis

Background: Psoriasis is a common immune-mediated inflammatory skin disease with strong genetic dispositions. Although more than 40 susceptibility loci have been revealed mostly through psoriasis genome wide association studies, genetic variants with small effect remain to be identified.

Objective: In order to explore the susceptibility genes with potential regulatory function, we queried jointly two psoriasis genome wide association cohorts and an expression dataset.

Methods: We integrated conventional genome-wide association evidences in 2326 Han Chinese and 2719 Caucasian populations, and the signature of expression quantitative trait loci (eQTL) in lymphoblastoid B cells, with application of Bayesian algorithm.

Results: Five genes with implied regulatory effect were revealed to be associated significantly with the risk of psoriasis, with one novel signal in FAM20B gene which is significantly expressed (P=3.24×10(-5)). Besides, seven single nucleotide polymorphisms were identified to be involved in the mechanism of psoriasis through eQTL effect.

Conclusions: We identified FAM20B as a risk regulatory gene in the etiology of psoriasis at first time. This study shed a spotlight on the immune regulatory mechanism in psoriasis.