IA-2, a member of the protein tyrosine phosphatase family; is a major auto antigen in type 1 diabetes.[65] IA-2 antibodies are more prevalent in patients with younger age of disease onset and in patients with diabetes susceptibility with HLA-DR4 alleles.[66] IA-2 antibodies are detected in 60–70% of type 1 diabetic patients and are associated with rapid progression to diabetes in relatives of patients.[67, 68]. This evidence concerns the gene PTPRN and diabetes mellitus.