HPGD and Thickened skin: Compared to those with PHOAR2 caused by SLCO2A1 defects, patients with PHOAR1 are six times more likely to be males than females, with clinical features of early-onset hypertrophic osteoarthropathy, milder pachydermia, gastrointestinal symptoms, and lower prevalence of arterial catheters (5, 6).