P19 A rare case of PHOAR2-enteropathy syndrome (PHOAR2E; previously known as pachydermoperiostosis) with a causal variant in the SLCO2A1 gene

Abstract We present a rare case of PHOAR2-enteropathy syndrome with a causal variant in the SLCO2A1 gene in an adolescent male who presented to the dermatology department for prominent deep creases on his forehead and fingers. He was described progressive enlargement of his hands and feet associated with hyperhidrosis.He was also complaining of knee and ankle swelling, limiting physical activities, ongoing for the last 4 years, treated by the rheumatology team as polyarticular juvenile idiopathic arthritis with tocilizumab, with no improvement. Recently, he described 2–3 episodes of loose stools a day. His medical history included acne. On examination, there were prominent deep creases on his forehead, seborrhoea, mild bilateral ptosis, enlarged hands with prominent creases of the fingers associated with mild clubbing of the nails, and bilateral knee swelling. Investigations revealed a normal full blood count, normal liver, kidney, and thyroid function, a mildly raised CRP and ESR, normal IGF1 levels, and a normal rheumatology workup. His faecal calprotectin and colonoscopy were normal. A skin biopsy was taken from the forehead, and histopathology showed marked dermal mucinosis without any follicular mucinosis or granuloma formation. Following a discussion in a dermatological complex cases meeting, a diagnosis of PHOAR2-enteropathy syndrome was proposed. Genetic testing identified a homozygous pathological variant (c.754C>T; p.Arg252*) in the SLCO2A1 gene, which confirmed the clinical diagnosis of PHOAR2-enteropathy syndrome. Tocilizumab was discontinued. Isotretinoin 20 mg daily, Etoricoxib 60 mg daily, and alendronate 70 mg weekly were introduced. At 3-month follow-up, a significant improvement was noted.