| Focal facial dermal dysplasia type III (FFDD3) is a rare focal facial dermal dysplasia with primary characteristics of congenital bitemporal scar-like depressions and a typical but variable facial dysmorphism. Caused by homozygous mutations in the TWIST2 gene, which encodes a bHLH transcription factor involved in dermal facial development in mammals. However, the majority of unrelated FFDD3 patients evaluated have had normal TWIST2 sequences, indicating the molecular genetic heterogeneity of the disorder. Many cases are sporadic. Inheritance is autosomal recessive for patients with TWIST2 mutations. |
