Primary Adrenal Insufficiency in a Boy with Type I Diabetes: The Importance of Considering X-linked Adrenoleukodystrophy.

Primary adrenal insufficiency (PAI) is often the first clinical sign of X-linked adrenoleukodystrophy (X-ALD), a rare genetic disorder that can present with various clinical phenotypes. A subset of boys with X-ALD develop cerebral ALD (cALD), characterized by progressive central demyelination, neurocognitive decline, and ultimately death. Timely intervention with hematopoietic cell transplant (HCT) can be a life-saving therapy by stopping progression of cerebral disease. We report the case of an 11-year-old boy with type 1 diabetes mellitus who presented with PAI, growth delay, and symptoms of attention deficit hyperactivity disorder. Given his history of T1DM, his PAI was presumed to be autoimmune and he was started on hydrocortisone and fludrocortisone. Eleven months later brain magnetic resonance imaging revealed white matter hyperintensity consistent with advanced cALD. The degree of disease progression at the time of diagnosis rendered the patient ineligible for transplant and he has continued to experience progressive neurologic decline. Initial symptoms of cALD are often subtle but should not be overlooked, as early identification of X-ALD is critical to allow early intervention with lifesaving HCT. PAI typically presents prior to the onset of neurologic symptoms. All boys who present with PAI should undergo workup for X-ALD with plasma very long chain fatty acid testing, even in the setting of underlying autoimmune disease.