Case report: Familial hypoparathyroidism with elevated parathyroid hormone due to an inactivating

Introduction: So far, only 11 Case description: The proband is a 34-year-old woman who has a history of chronic severe hypocalcemia (HypoCa) since birth. She and her three brothers (33-year-old male twins, and a 21-year-old male) were diagnosed with pseudohypoparathyroidism type 1b (PHPT 1b) based on the presence of chronic HypoCa (serum Ca 1.6-1.85 mmol/l) since birth associated with significantly elevated plasma PTH levels in the range of 310-564 pg/dl (normal range 10-65) and absence of signs of Albright hereditary osteodystrophy. Molecular studies: WES showed no pathogenic, likely pathogenic or variants of unknown significance in any known calcium-associated genetic disorder but a bi-allelic variant in the Management: Because the patient's HypoCa was not controlled on large doses of calcitriol and calcium carbonate, a trial of teriparatide 20 mcg SC daily was started and resulted in normalization of calcium, decline in PTH levels and significant improvement in her general wellbeing. Conclusion: High PTH in the presence of congenital hypocalcemia is not always due to receptor or post-receptor defect and can be due to a biologically inactive mutated PTH. In such cases, treatment with teriparatide may result in stabilization of biochemical profile and improvement in quality of life.