Possible causes of thyroid dysgenesis include the impact of maternal antithyroid immunoglobulins, genetic mutations, genes of transcription factors TTF1, TTF2 and PAX8, and HHEX found in functional thyroid cells, but also in their precursors, which are essential for the early stages of thyroid morphogenesis [4,5]. This evidence concerns the gene HHEX and thyroid gland disorder.