The focal dermal dysplasias (FFDDs) are a group of related developmental defects characterized by bitemporal or preauricular skin lesions resembling aplasia cutis congenita. FFDD4 is characterized by isolated, preauricular skin lesions (summary by Slavotinek et al., 2013).
For a classification and a discussion of genetic heterogeneity of FFDD, see FFDD1 (136500). [from
OMIM]