Thus, while analyzing hyponatremia, it is imperative to not only verify that a certain degree of inappropriate AVP release is present (“concurrent AVP release”), but also to ascertain whether it in itself—that is, in the absence of significant hypotonic fluid intake—can sufficiently explain the observed hyponatremia (“sufficient AVP release”) in order to understand the pathophysiological mechanism(s) at play. This evidence concerns the gene AVP and Hyponatremia.