This congenic strain, named NOD-H2h4, carries the thyroiditis susceptible k allele at the MHC class II A locus (Kk, Ak, E0, Db), and develops a chronic, lymphocyte rich form of thyroiditis [50] associated with the development of Tg antibodies (Abs) and then TPO Abs [51]. The gene discussed is TPO; the disease is thyroiditis.