Brachydactyly type B

Brachydactyly type B is inherited in an autosomal dominant manner. This means that having a change (mutation) in only one copy of the responsible gene in each cell is enough to cause features of the condition. There is nothing that either parent can do, before or during a pregnancy, to cause a child to have this condition.

In some cases, an affected person inherits the mutation from an affected parent. In other cases, the mutation occurs for the first time in a person with no family history of the condition.

When a person with a mutation that causes an autosomal dominant condition has children, each child has a 50% (1 in 2) chance to inherit that mutation.

Brachydactyly type B (BDB) is 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.