21-hydroxylase Autoantibody-negative Addison's Disease in a 5-year-old Boy with Adrenal Crisis and Type 1 Diabetes Mellitus

Abstract

Patients with type 1 diabetes mellitus (T1DM) have an increased risk of other autoimmune disorders. The combination of Addison's disease with T1DM and/or autoimmune thyroid disease is known as autoimmune polyendocrinopathy type 2 (APS-2). 21-hydroxylase autoantibody (21OHAb) is considered as a valuable marker for identifying patients with autoimmune Addison's disease (AD); however, it is not available in some countries. Here we present a 5-year-old boy with newly diagnosed T1DM, who developed AD with adrenal crisis within only six months, and after 1-year treatment, the test of 21OHAb was negative. This was a rare and the first APS-2 case in Taiwan, because APS-2 affects female adults more often, but not boys. At diagnosis of T1DM, we suggest that checking diurnal cortisol and adrenocorticotropic hormone levels as a baseline evaluations, and if it is available, checking 21OHAb as well. If there is subtle evidence of AD, such as unexplained hypoglycemia or unreasonably reduced insulin requirements, adrenal functions must be studied as soon as possible, even in the 21OHAb-negative T1DM patients. Even if nothing is abnormal, the patient still needs an annual measurement.