Primary hypertrophic osteoarthropathy with severe arthralgia identified by gene mutation of SLCO2A1

Male, 41 years old (yo) had been complaining of severe arthralgia. Past History indicated obstruction of intestinal tract at 12 yo and gastric ulcer at 13 yo. He had been suffered from polyarthralgia especially at PIP and MP joints of both hands from 38 yo. Finally, he complained severe arthralgia at PIP and MP joints with clubbed fingers without swelling. Biochemical finding indicated negative rheumatoid factor and anti-CCP antibody and normal MMP-3 level, but slightly increased CRP and ESR levels. Radiological finding indicated periostosis of　long bone without bone erosion and osteoporosis. His facial appearance was acromegalic with cutaneous manifestation of pachydermia and cutis vertices gyrate without abnormal growth hormone response. Histological findings of skin indicated oedema and hyperplasia of sebaceous glands with infiltration of lymphocytes around small blood vessels compatible with pachydermoperiostosis. In this case mutation of SLCO2A1 gene, which coded prostaglandin transport protein, was identified. The mutation c.940 + 1G > A of SLCO2A1 gene results in deletion of exon 7 and truncation of PG transporter (p.Arg288Glyfs*7). We suggest that severe arthralgia was originated from over production of prostaglandin E2. Further studies will be required.