The focal dermal dysplasias (FFDDs) are a group of related developmental defects characterized by bitemporal or preauricular skin lesions resembling aplasia cutis congenita. Cervantes-Barragan et al. (2011) proposed a classification of FFDD in which there are 4 subtypes. FFDD1 (Brauer syndrome) is characterized by temporal skin depressions that resemble 'forceps marks.' Other facial anomalies, comprising sparse lateral eyebrows, distichiasis, and a flattened nasal tip, are usually mild. Inheritance is autosomal dominant. FFFD2 (Brauer-Setleis syndrome; 614973) is characterized by bitemporal skin lesions with variable facial findings, including thin and puckered periorbital skin, distichiasis and/or absent eyelashes, upslanting palpebral fissures, a flat nasal bridge with a broad nasal tip, large lips, and redundant facial skin. Inheritance is autosomal dominant. FFDD3 (Setleis syndrome; 227260) is characterized by the same facial features as FFDD2, but the inheritance is autosomal recessive. FFDD4 (614974) is characterized by isolated, preauricular skin lesions with autosomal dominant or recessive inheritance (summary by Slavotinek et al., 2013).
Genetic Heterogeneity of Focal Facial Dermal Dysplasia
FFDD3 (227260) is caused by mutation in the TWIST2 gene (607556) on chromosome 2q37. FFDD4 (614974) is caused by mutation in the CYP26C1 gene on chromosome 10q23. [from
OMIM]