PTPRN and type 1 diabetes mellitus: in the Finnish population-based Diabetes Prediction and Prevention (DIPP) type 1 study, which aims to monitor the emergence of anti-islet autoantibodies in children with increased HLA-dependent susceptibility to T1D, showed high sensitivity of ICA in identifying clinical disease progression, but unlike previously published 5-year follow-up data, lower specificity than other autoantibodies tested by biochemical methods (IAA, GADA, IA2) (36).