The fundamental role of AVPR2 in regulating the body’s water and electrolyte balance is highlighted by the human phenotype resulting from inactivating mutations of the receptor, which cause a rare congenital disease, X-linked nephrogenic diabetes insipidus (XNDI) characterized by exacerbated polyuria (up to 20 L of urine produced in 24 h) and constant risk of severe dehydration [21,22,23,24,25,26,27]. Here, AVPR2 is linked to nephrogenic diabetes insipidus.