Comparative genetic analysis of psoriatic arthritis and psoriasis for the discovery of genetic risk factors and risk prediction modelling

The objective was to identify genetic risk factors and pathways that differentiate PsA from cutaneous‐only psoriasis (PsC) and to evaluate the performance of PsA risk prediction models. The study identified a novel genome‐wide significant susceptibility locus for PsA on chromosome 22q11, and key pathways that differentiate PsA from PsC including NF‐kB signalling and WNT signalling. Modest performance of published classification pipelines (max AUC 0.61) was observed with similar performance for a risk model derived from the current data. Key biological pathways associated with PsA were identified. Still, the investigation of risk classification revealed modest utility in the available datasets, possibly because many of the PsC patients were receiving treatments that are also effective in PsA; future predictive models of PsA should be tested in PsC patients recruited from primary care.