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Familial hypocalciuric hypercalcaemia type 3: AP2S1 missense mutation
  1. Sarah Kerut1,
  2. Karthik Reddy Kovvuru2,
  3. Licy Yanes-Cardozo2 and
  4. Vishnu Vardhan Garla2
  1. 1Internal Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
  2. 2Mississippi Center for Clincal and Translational Center, University of Mississippi Medical Center, Jackson, Mississippi, USA
  1. Correspondence to Dr Vishnu Vardhan Garla; vishnu.garla{at}


A 45-year-old man was referred to endocrine for the evaluation of hypercalcaemia. The calcium was elevated, vitamin D was low with a normal parathyroid hormone. Dual-energy X-ray absorptiometry scan revealed osteoporosis at the lumbar spine and femoral neck. A 24-hour urine collection revealed low urinary calcium, which was believed to be secondary to vitamin D deficiency. A diagnosis of primary hyperparathyroidism was made. The patient underwent a four-gland parathyroid exploration surgery in which three of his parathyroid glands were removed. The pathology was consistent with benign parathyroid tissue. Post surgery, the patient had persistently elevated calcium levels. He was then started on bisphosphonate and cinacalcet for osteoporosis and hypercalcaemia, respectively. Genetic analysis of familial hypocalciuric hypercalcaemia (FHH) showed a p.arg15cys mutation in the AP2S1 gene, confirming the diagnosis of FHH type 3.

  • endocrine system
  • calcium and bone

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  • Contributors SK and KRK were involved in writing the case description. LYC and VVG were involved in editing and writing the discussion section.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Obtained.

  • Provenance and peer review Not commissioned; externally peer-reviewed.

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