LAUSR

We have recently shown that the detection of monogenic diabetes in a population can be improved by excluding individuals with type 1 diabetes (T1D) identified by having low C-peptide levels and/or the presence of GAD autoantibodies (GADA) or IA-2 autoantibodies (IA-2A) in the Using pharmacogeNetics to Improve Treatment in Early-onset Diabetes (UNITED) study (1). Since completion of the study, there are now two new tests that also robustly identify T1D: zinc transporter 8 autoantibodies (ZnT8A) (2) and the T1D genetic risk score (T1D GRS) (3,4). It is not known the extent to which the addition of these new tests will improve the diagnostics (1). Autoantibodies assessment was performed at recruitment. The median duration of diabetes at recruitment was 7.4 years (interquartile range [IQR] 2.5–17.3). GADA and IA-2A were measured as previously described (1). ZnT8A was measured by ELISA (RSR Ltd, Cardiff, U.K.) on a Dynex DS2 ELISA robot (Dynex, Preston, U.K.). The RSR ZnT8A ELISA is capable of detecting and quantifying autoantibodies specific to R325 or to W325, or to residue 325 nonspecific variants. We used >99th centile of a control population ( n = 1,559, age range …