Familial Aggregation in Psoriatic Arthritis: Phenotypic Differences in Patients with and without a Family History of Psoriatic Disease

ObjectivesWhile up to 45% of patients with psoriatic arthritis (PsA) have a family history of psoriatic disease, it is unclear whether this family history contributes to a distinct PsA phenotype and/or timing of disease onset. We aimed to identify differences in onset, domain involvement, and disease activity based on family history of psoriatic disease.Methods843 PsA patients were enrolled in an observational, longitudinal registry. Demographics, medical history, family history, and psoriatic phenotype and activity were collected.Results379 patients (45.0%) had at least one first‐degree (FDR) or second‐degree relative (SDR) with psoriatic disease. Those with a family history developed psoriasis and PsA earlier than those with no family history (27.6 vs. 32.2 years, p < 0.01; 37.6 vs. 40.3, p < 0.01) and were more likely to have entheseal involvement (36.7% vs. 30.0%, p < 0.05). Patients with an FDR/SDR with PsA were diagnosed with psoriasis and PsA earlier than those with an FDR/SDR with psoriasis alone, followed by those with no family history (26.3 vs. 27.8 vs. 32.2 years, p < 0.01; 36.5 vs. 37.9 vs. 40.3 years, p = 0.01).ConclusionIn this cohort, PsA patients with a family history of psoriatic disease were diagnosed with psoriasis and PsA earlier, and were more likely to have entheseal involvement, compared to those without a family history. Further research incorporating molecular and immune features is needed to investigate genetic, environmental and epigenetic factors that impact PsA phenotype and severity, as well as the transition from psoriasis to PsA.