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Abstract: SA-PO310

A Case of Primary Pseudohypoparathyroidism Presenting with Normal Serum Phosphorus

Session Information

Category: Bone and Mineral Metabolism

  • 502 Bone and Mineral Metabolism: Clinical

Authors

  • Ghodrati, Kian, Wilfrid Laurier University Faculty of Science, Waterloo, Ontario, Canada
  • Prakash, Vikyath, Dallas Renal Group, Dallas, Texas, United States
  • Nangia, Samir, Dallas Renal Group, Dallas, Texas, United States

Group or Team Name

  • Dallas Renal Group.
Introduction

Pseudohypoparathyroidism (PHP) is a very rare genetic disorder characterized by hypocalcemia/hyperphosphatemia secondary to parathyroid hormone (PTH), target organ resistance. PHP is a congenital disorder that is diagnosed in childhood. This is a unique presentation of a rare condition that was initially diagnosed in adulthood.

Case Description

We present a unique case of a 37-year-old woman who was referred for a second opinion before undergoing parathyroidectomy for a positive nuclear scan with an elevated intact parathyroid hormone (iPTH). She had a history of hypocalcemia beginning in her 30s with no family history for the same. Physical exam revealed short stature but no brachydactyly or intellectual disability. Initial findings showed a corrected serum calcium level was 8.3, iPTH 214, vitamin D 44, phosphate 3.6, magnesium 2.1, bicarbonate 25, and creatinine 0.9 and was placed on calcium supplementation and calcitriol. The urinary Fractional excretion of calcium was elevated and her bone density scan was normal. She was treated with a thiazide diuretic and an increase in the calcitriol dose which led to a corrected serum calcium 9.1 and iPTH 93. She did not undergo parathyroidectomy and we can conclude she likely has pseudohypoparathyroidism 1a or 1c.

Discussion

To our knowledge, this is one of the first reported cases of PHP diagnosed with normal serum phosphorus levels. The current literature review does not examine patients that have PHP despite having normal serum phosphorus levels. The goal of this case report was to increase awareness and education that PHP can be diagnosed later in life due to its varying phenotypic penetrance. Future studies can examine a larger cohort of patients that present with similar symptoms to determine the genetic cause. Above all, it is essential to provide knowledge to patients as well as physicians alike.