PTH and Hypocalcemia: It was an interesting observation that many patients with POD1 PTH ≥ 15 pg/ml who developed symptoms had a history of Graves disease or hyperthyroidism; however, in this series, we were not able to conclusively demonstrate an association between Graves disease and development of symptomatic hypocalcaemia in patients with POD1 PTH ≥ 15 pg/ml.