KITLG and Werner syndrome: To date, seven genes have been associated with the different types of WS: endothelin receptor type B—EDNRB (WS4); KIT ligand—KITLG (WS2); melanocyte-inducing transcription factor—MITF (WS2); paired box 3—PAX3 (WS1, WS3); snail family transcriptional repressor 2—SNAI2 (WS2); SRY-box transcription factor 10—SOX10 (WS2, WS4); and endothelin 3—EDN3 (WS4).