Hypoparathyroidism results from the destruction or dysfunction of the parathyroid glands and leads to a permanent or transient lack of PTH, most commonly caused by thyroidectomy-associated inadvertent damage/removal of the parathyroid glands [82], whereas it is rarely associated with parathyroidectomy (PTX), autoimmunity, Di-George syndrome, activating mutations of the CASR gene, and inactivating mutations of the glial cell missing 2 (GCM2) transcription factor or PTH genes. Here, PTH is linked to hypoparathyroidism.