Furthermore, four missense loss of function SUR1 mutations have been identified in patients with either PAH or congenital hyperinsulinism (CHI), without overlap of these clinical syndromes, and four variants are associated with both PAH and CHI, suggesting variable penetrance and/or expressivity in the variety of tissue types that rely on SUR1 function [12]. Here, ABCC8 is linked to congenital isolated hyperinsulinism.