The events that underlie the conversion from Psoriasis to Psoriatic Arthritis (PsA) are not well understood. This conversion occurs 30% of the time within the first 10 years of psoriasis diagnosis. PsA patients have about a 50% chance of developing joint damage within the first 2 years of disease. A biomarker that identifies subclinical joint inflammation in psoriasis patients would allow for a diagnostic tool to allow for earlier intervention in psoriasis patients and provide a better understanding of the underlying molecular pathogenesis that may lead to development of new therapeutic targets in PsA.