Aterido A, et al. - In this genome-wide association study, 835 cases with Psoriatic arthritis (PsA) and 1558 controls from Spain were examined to distinguish the genetic variation particular for PsA using a purely cutaneous psoriasis cohort (PsC) and a rheumatoid arthritis cohort. Researchers recognized a new PsA risk single-nucleotide polymorphism at B3GNT2 locus. Fourteen genetic pathways significantly associated with PsA were recorded at the pathway level. After comparing the PsA cohort and cohorts of subjects with PsC and RA, they confirmed the glycosaminoglycan (GAG) metabolism pathway to be disease-specific.