ESR1 and thyroiditis: We exploited the thyroiditis susceptibility of the NOD-H2h4 strain to create a new mouse model where autoimmune thyroiditis and PTC can be induced in a temporally definable fashion [54]: we backcrossed onto the NOD-H2h4 strain the TPO-CRE-ER transgenic strain [42] and the BRAFV600E knock-in strain [41] for a minimum of 16 generations [54].