Mutations in the gene encoding the transcription factor interferon regulatory factor 6 (IRF6), cause VWS and PPS, both characterized by ectodermal anomalies and CL/P or CP; mutations in the transcription factor p63 cause autosomal dominant ectodermal dysplasia syndromes such as ectrodactyly ectodermal dysplasia-clefting (EEC), which is also characterized by CL/P or CP and defects in ectoderm-derived tissues, such as the epidermis, hair, teeth, and glands (76). Here, IRF6 is linked to popliteal pterygium syndrome.