This study aimed to investigating the host susceptibility to the psoriasis and the association of (Rs1184860, Rs1167846 and Rs1167849) single nucleotide polymorphisms (SNPs) in the Interleukin -20 Receptor A (IL- 20RA) gene, located on chromosome 6q22.33-23.1, and detecting late cornified envelope 3B and late cornified envelope 3C (LCE3B and LCE3C) genes mutations. These genes encode members of late cornified envelope gene cluster, and are in the region that contains the Psoriasis Susceptibility gene-4 (PSORS4) locus on chromosome 1q21, and the role of interleukins (IL-17A, IL-23) and Human papillomavirus in the pathogenesis of this disease.