- Extreme hyperopia is the result of null mutations in MFRP, which encodes a Frizzled-related protein. Sundin, O.H., Leppert, G.S., Silva, E.D., Yang, J.M., Dharmaraj, S., Maumenee, I.H., Santos, L.C., Parsa, C.F., Traboulsi, E.I., Broman, K.W., Dibernardo, C., Sunness, J.S., Toy, J., Weinberg, E.M. Proc. Natl. Acad. Sci. U.S.A. (2005)