In primary hypertrophic osteoarthropathy (pachydermoperiostosis), gene-mutations of the prostaglandin degrading enzyme, 15-hydroxyprostaglandin dehydrogenase (HPGD) and the PG transporter (SLCO2A1) lead to impairment of PGE2 degradation. The gene discussed is HPGD; the disease is primary hypertrophic osteoarthropathy.