Thyroid dysgenesis is caused by genes (thyroid transcription factor-1 [TTF-1], thyroid transcription factor-2 [TTF-2], and paired box 8 [PAX-8]) associated with syndromic CH and those causing non-syndromic CH (thyroid-stimulating hormone receptor [TSHR]) [5]. This evidence concerns the gene TSHR and cyclic hematopoiesis.