Cystic multiglandular maternal hyperparathyroidism diagnosed by neonatal hypocalcemic seizures.

A 7-day-old male infant born to a healthy 33-year-old female at 37 weeks of gestation was brought to the local emergency department (ED) with sudden-onset tonic-clonic seizures. Laboratory testing revealed extreme hypocalcemia (ionized calcium of 3.2 mg/dl) and undetectable parathyroid hormone (PTH <10 pg/ml).