PAX8 and thyroiditis: Although the actual cause of thyroid dysgenesis is still under investigation, some studies have suggested that 4 major genes that play roles in the proper growth and development of the thyroid gland, such as TSHR (Thyroid 3 stimulating hormone receptor) and three transcription factors- TTF-1, TTF-2, and PAX8 (paired box-8, transcription factor) [2].