Endocrine Abstracts

Primary hyperparathyroidism (PHPT) is a relatively common endocrine disorder, and more than 10% of affected individuals carry mutations in one of several implicated genes. Genetic testing can play a pivotal role in guiding the management and surveillance of patients with PHPT. We report the case of a 38-year-old woman with asymptomatic hypercalcemia identified during the third trimester of pregnancy, with an adjusted calcium level of 3.01 mmol/l (reference range: 2.20–2.57 mmol/l). Postpartum evaluation confirmed PHPT, with an adjusted calcium of 3.19 mmol/l and parathyroid hormone (PTH) concentration of 156 ng/l (reference range: 15–65 ng/l). Parathyroid sestamibi imaging revealed a right-sided adenoma. Her brother had previously undergone parathyroidectomy for PHPT in his 30s. Given her age and family history, genetic testing was undertaken and identified a pathogenic CDC73 mutation, confirming hyperparathyroid jaw tumor syndrome (HPT-JT). This rare autosomal dominant disorder is associated with parathyroid adenomas, parathyroid carcinomas, ossifying fibromas of the jaw, renal cysts or neoplasms, and uterine abnormalities. The patient underwent a two-gland parathyroidectomy, and histology confirmed parathyroid adenomas. Postoperatively, calcium and PTH levels normalized. Screening for associated complications showed no evidence of jaw, renal, or uterine involvement. Genetic testing of her children revealed that two of her three children also carry the mutation and are undergoing clinical surveillance. This case highlights the importance of genetic evaluation in young patients with familial PHPT. Early identification of HPT-JT enables appropriate surveillance and intervention, potentially reducing morbidity and improving long-term outcomes.