CASR and 22q11.2 deletion syndrome: When reported, the most frequent etiologies of hypoparathyroidism were postsurgical (281/401 patients, 70%) followed by idiopathic, autoimmune (polyglandular failure), and genetic causes (DiGeorge syndrome; hypoparathyroidism, deafness, and renal disease syndrome; calcium sensing receptor activating mutations), as reported in Tables 1 and 2.