The diagnosis of adrenal insufficiency in a patient with Allgrove syndrome and a novel mutation in the ALADIN gene

Allgrove syndrome is a genetic disorder inherited in an autosomal recessive pattern and characterized by a triad of adrenal insufficiency, achalasia, and alacrima. The gene affected by the mutation in patients with Allgrove syndrome is termed either AAAS or ALADIN (alacrima/achalasia/adrenal insufficiency/ neurologic disorder). Adrenal insufficiency in patients with this disorder may develop as late as the third decade of life. We describe a 24-year-old female with Allgrove syndrome, in whom initial testing with 250 μg corticotropin (ACTH) stimulation test performed on 3 occasions produced normal serum cortisol values and results of the 1-μg ACTH stimulation tests performed on 6 occasions were conflicting. Insulin-induced hypoglycemia produced a nadir serum glucose value of 36 mg/dL without adequate serum cortisol stimulation, confirming presence of adrenal insufficiency. Gene sequencing identified 2 mutations in the triple A gene: an IVSC14 +1 G to A mutation, which has been previously reported, and a novel R155P exon 6 mutation. We conclude that a novel R155P mutation in the ALADIN gene is associated with Allgrove syndrome and that insulin-induced hypoglycemia, rather than ACTH stimulation tests, should be used for accurate diagnosis of adrenal insufficiency in this disorder.