2020 Volume 63 Issue 9 Pages 626-633
A 61-year-old woman treated with insulin therapy who had been diagnosed with anti-GAD antibody-positive acute-onset type 1 diabetes (AT1D) 5 years earlier was admitted to our hospital with dementia-like symptoms. Her blood test revealed macrocytic anemia and vitamin B12 deficiency. Thereafter, atrophic glossitis and atrophic gastritis were confirmed, and anti-gastric parietal cells antibodies were detected, leading to the diagnosis of pernicious anemia (PA) associated with AT1D. A combination of type 1 diabetes and PA has been observed, typically in cases of autoimmune polyglandular syndrome type III (APS III) with slowly progressive insulin-dependent diabetes mellitus (SPIDDM). Because this patient had no history of autoimmune thyroid diseases, the diagnosis of APS III was excluded. Furthermore, there have been no reports of non-APS III with correctly diagnosed autoimmune-mediated AT1D associated with PA other than our case at least in Japan. The mechanism underlying the combination of autoimmune-mediated AT1D and PA may be immunologically distinct from that of SPIDDM and PA in previous APS III cases.
