brachydactyly type B
A condition characterized by incomplete development (hypoplasia) or absence of the outermost bones of the fingers and toes (distal phalanges) and nails. Additional features may include hypoplasia of the middle phalanges, fusion of the joints (symphalangism), broad thumbs, and webbed fingers (syndactyly). The feet are often less severely affected than the hands. There are 2 types of this condition, designated as type 1 and 2. BDB type 1 is caused by mutations in the ROR2 gene. BDB type 2 is caused by mutations in the NOG gene. Inheritance of both types is autosomal dominant. Treatment may include surgery if the condition affects hand function, or for cosmetic reasons.