SLCO2A1 and primary hypertrophic osteoarthropathy: Considering the importance of prostaglandin transporter in the regulation of prostaglandin action in the menstrual cycle of human female (22, 46, 47), we postulated that some hormones might protect female from the severe symptom of PHO in skin and bones, which hinted a potential hormone therapeutics for the temporary unaffected preadolescent male probands.