HPGD and primary hypertrophic osteoarthropathy: Two genes were found to be associated with PHO: HPGD (OMIM 601688) and SLCO2A1 (OMIM 601460), which encode 15-hydroxyprostaglandin dehydrogenase (15-PGDH) and prostaglandin transporter (PGT, also known as solute carrier organic anion transporter family member 2A1), respectively.