SORT1 and Polydipsia: Hypothalamic dysfunctions have been observed in some other mouse models of neurodegenerative diseases [60, 61], and primary polydipsia was found in saposin D deficient mice [26], the latter important because its precursor, prosaposin and progranulin converge on sortilin-mediated transport, interaction at the autophagolysosomal interface [16] and lysosomal functions [18, 62].