Recent findings on fulminant type 1 diabetes.

Fulminant type 1 diabetes (fT1D) is a new subtype of type 1 diabetes proposed by Imagawa in 2000. It is a clinical syndrome characterized by a markedly rapid and almost complete destruction of pancreatic β cells. Metabolic derangement is more severe in this subtype than in autoimmune type 1 diabetes. The incidence of fT1D is associated with HLA DRB1*04:05DQB1*04:01; both innate and acquired immune disorders might contribute to the development of fT1D. The presence of specific innate immune responses to enterovirus infection connected with enhanced adaptive immune pathways responsible for aggressive β cell toxicity in fT1D. The process of β cell destruction is extremely rapid in fT1D, and the insulin secretary capacity rarely recovers after the onset. The serum glycated albumin to glycated haemoglobin ratio is significantly higher in fT1D; a cut-off value of 3.2 for serum glycated albumin to glycated haemoglobin ratio yielded 97% sensitivity and 98% specificity for differentiating fT1D from type 2 diabetes. Fulminant type 1 diabetes is associated with pregnancy. This article also updates the diagnostic criteria for fT1D by the Japanese Diabetes Association in 2012.