| Focal facial dermal dysplasia type IV (FFDD4) is a rare focal facial dysplasia with characteristics of congenital isolated preauricular and/or cheek blister scar-like lesions. Affected FFDD4 patients typically do not present with extra-cutaneous manifestations, although in a small number of cases, a hair collar sign (circumscription of the cutaneous lesion with terminal hairs), polyps on the buccal mucosa with a similar distribution pattern, and developmental delay have been reported. An autosomal recessive trait. |
