- Mutations of the Uromodulin gene in MCKD type 2 patients cluster in exon 4, which encodes three EGF-like domains. Wolf, M.T., Mucha, B.E., Attanasio, M., Zalewski, I., Karle, S.M., Neumann, H.P., Rahman, N., Bader, B., Baldamus, C.A., Otto, E., Witzgall, R., Fuchshuber, A., Hildebrandt, F. Kidney Int. (2003)