A Loss-of-Function Variant Causing Primary Autosomal Recessive Hypertrophic Osteoarthropathy.

Primary autosomal recessive hypertrophic osteoarthropathy (PHOAR) type 1 is caused by the failure of the HPGD gene product to break down prostaglandins. We report the case of a two-year-old male patient diagnosed with PHOAR1 due to a previously unreported homozygous intragenic deletion. Upon retrospective review of the patient's history, his clinical course proved to be typical of this syndrome, although it had been unrecognized. This case report presents an opportunity to review the natural history, clinical signs, diagnosis, and treatment of PHOAR1, with the aim of raising awareness of this rare entity.