Maternal primary hyperparathyroidism: discordant outcomes in a twin pregnancy.

The case reports a neonate (twin 2 of a twin girl pregnancy) presenting with seizures due to hypocalcaemia. The presumptive cause of the hypocalcaemia was maternal hyperparathyroidism with concurrent vitamin D deficiency. The first twin remained free of hypocalcaemia and was vitamin D replete, despite similar exposure in the pregnancy and similar postnatal care.