SLC9A3 and hyperinsulinemic hypoglycemia, familial, 4: At 15 weeks, the age chosen to limit mortality associated with compound NHE3/Apc deficiency, F2 cross between B6 ApcMin/+ and 129 Sv/Ev NHE3−/− housed in a barrier facility did not exhibit macroscopically evident small intestinal pathology (data not shown).