The PTPN22 gene was significantly associated with susceptibility to psoriatic arthritis but was not related to psoriasis risk, according to Dr. John Bowes and his associates.
In a total sample of 3,139 psoriatic arthritis (PsA) cases and 11,078 controls, the investigators tested 13 single-nucleotide polymorphisms and found 2 to be significantly associated with PsA, rs4795067 and rs2476601. The single-nucleotide polymorphism rs4795067, which maps to the NOS2 gene, was already known as a risk locus, but rs2476601, which maps to PTPN22, was not. The odds ratio for PTPN22 was 1.32, slightly more than the OR for the previously known NOS2 locus at 1.22.
“The identification of PsA-specific loci is vital in terms of understanding the different pathways involved, which may require different treatments, and for future screening strategies to identify subjects at risk of developing PsA in patients with psoriasis,” the investigators wrote.
Read the full study in Annals of the Rheumatic Diseases (doi:10.1136/annrheumdis-2014-207187).