INS and hypopituitarism: All affected siblings of families III and IV at the time of diagnosis of hypopituitarism initially showed sufficient cortisol responses to the insulin tolerance test (ITT) (Table 1); then at some point during their years of follow-up, hydrocortisone was empirically commenced when they presented with symptoms of fatigue and borderline morning cortisol levels (6–17 μg/dL) (Table 1).