Proximal symphalangism 1B
Symphalangism of the Cushing type 1B is an autosomal dominant disorder caused by mutations of the GDF5 gene. It is characterized by fusion of proximal interphalangeal joints, carpals, tarsals, and sometimes conductive hearing loss.
Seemann P et. al. (2005) Activating and deactivating mutations in the receptor interaction site of GDF5 cause symphalangism or brachydactyly type A2.[^]
Wang X et. al. (2006) A novel mutation in GDF5 causes autosomal dominant symphalangism in two Chinese families.[^]
Yang W et. al. (2008) Novel point mutations in GDF5 associated with two distinct limb malformations in Chinese: brachydactyly type C and proximal symphalangism.[^]