Unexpected Hyperparathyroidism in A Patient With Acrodysostosis

Abstract

Objective: Acrodysostosis is a rare skeletal dysplasia with one gene mutation associated with pseudohypoparathyroidism. We describe a 15-year-old male patient with genetically proven acrodysostosis who presents with hyperparathyroidism. Methods: Laboratory testing including genetic testing for acrodysostosis and biochemical evaluation for hypercalcemia were obtained. For evaluation of the source of hyperparathyroidism, parathyroid imaging including sestamibi scan, ultrasound, and 4DCT scan were performed. Results: Initial calcium 11.7 mg/dL (8.4–10.2), phosphorus 2.6 mg/dL (2.9–5.0), and PTH 177 pg/ml (15–65) were suspicious for hyperparathyroidism. Magnesium, albumin, creatinine, and PTHrP levels were normal. His Ca/Cr ratio was 0.15, calcium/creatinine clearance ratio was 0.008 and the fractional excretion of phosphorus was 34%. Our patient had no symptoms other than long standing bone pain. Thyroid ultrasound, then sestamibi scan did not show a parathyroid adenoma nor parathyroid gland hyperplasia. Familial hypocalciuric hypercalcemic syndrome (FHH) was entertained, but without a family history and documented normal calcium levels throughout childhood, FHH was unlikely. On subsequent testing, his calcium and PTH levels increased. Subsequent imaging including repeat thyroid ultrasound, Sestamibi scan, and CT scan have not found a definitive cause. MEN1 genetic testing was negative. Without an adenoma seen to remove surgically, we performed a trial of cinacalcet with successful reduction in PTH and normalization of his calcium and phosphorus levels. Conclusion: Pseudohypoparathyroidism and hypocalcemia are well reported in acrodysostosis. To the best of our knowledge, this is the first reported case of hypercalcemia caused by hyperparathyroidism in a patient with acrodysostosis.