This additional level of regulation has been discovered in several specific cases such as the Microphthalmia-associated transcription factor (MITF) regulation by SOX-10 and PAX-3 in the Waardenburg syndrome [41], the modulation of chondrogenesis onset by Runx [42], the specification of lymphoid cell fates [43], or the ESC regulatory circuitry [44], [45]. Here, PAX3 is linked to Waardenburg syndrome.