Although there is no consensus regarding the usage of vasopressin as a diagnostic marker for MD, most publications agree that vasopressin might reflect the status of MD attack in MD patients [8], probably because the overexpression and hyperactivity of V2R in the endolymphatic sac of MD patients develop EH and vertigo attacks after vasopressin elevation [139]. The gene discussed is AVPR2; the disease is Menkes disease.