- PTPRC (CD45) is not associated with the development of multiple sclerosis in U.S. patients. Barcellos, L.F., Caillier, S., Dragone, L., Elder, M., Vittinghoff, E., Bucher, P., Lincoln, R.R., Pericak-Vance, M., Haines, J.L., Weiss, A., Hauser, S.L., Oksenberg, J.R. Nat. Genet. (2001)