AVPR2 and nephrogenic syndrome of inappropriate antidiuresis: The term “nephrogenic syndrome of inappropriate antidiuresis (NSIAD)” was also coined by Feldman et al. when they described two infants whose clinical and laboratory evaluations were consistent with the presence of the SIADH but had undetectable AVP because of gain-of-function mutations in the V2R (Feldman et al., 2005).