EDN3 and Waardenburg syndrome: There are four types of Waardenburg syndrome, classified by symptom and primarily caused by six genetic mutations: melanocyte inducing transcription factor (Mitf), paired box 3 (Pax3), SRY-box transcription factor 10 (Sox10), Ednrb, endothelin 3 (Edn3), and snail family transcription factor 2 (Snai2) (reviewed in Song et al., 2016).