- Mutations in bone morphogenetic protein receptor 1B cause brachydactyly type A2. Lehmann, K., Seemann, P., Stricker, S., Sammar, M., Meyer, B., Süring, K., Majewski, F., Tinschert, S., Grzeschik, K.H., Müller, D., Knaus, P., Nürnberg, P., Mundlos, S. Proc. Natl. Acad. Sci. U.S.A. (2003)