A 14-year-old previously healthy Caucasian boy presented to the Pediatric Rheumatology clinic with 6 months history of progressive distal extremity swelling, weakness, functional limitation, and 12kg weight loss. There were no fevers or night sweats. The remainder of the review of systems was unremarkable. Physical examination demonstrated bilateral distal extremity swelling of all four limbs; clubbing in all digits; and polyarthritis involving knees, ankles, and proximal interphalangeal joints of the hands (Figure 1a).