Many of the research studies designed to quantify autoantibodies to GAD65, IA-2 and ZnT8 in type 1 diabetes have used radioligand binding assays in which radiolabelled antigen is generated by transcription and translation of the protein in vitro using appropriate plasmid constructs in the presence of radiolabelled amino acid. This evidence concerns the gene PTPRN and type 1 diabetes mellitus.