Following the identification of 2 different ETAR missense variants, Y129F and E303K, in MFDA, we report here another patient with MFDA harboring the E303K mutation in a mosaic state and mouse models carrying the ETAR-Y129F or -E303K mutations, which mostly recapitulate morphological manifestations of MFDA. The gene discussed is EDNRA; the disease is mandibulofacial dysostosis with alopecia.