GNA11 and Hypocalcemia: With the discovery that mutations in the gene encoding the alpha subunit of the G protein G11 (GNA11) cause hypocalcemia, ADH was divided into type 1, reviewed above, and type 2, caused by activating mutations in GNA11. Patients with ADH2 present with a wide range of hypocalcemic symptoms ranging from paresthesias to tetany and seizures, or they can be asymptomatic.