- Abnormalities induced by the mutant gene, lpr. Patterns of disease and expression of murine leukemia viruses in SJL/J mice homozygous and heterozygous for lpr. Morse, H.C., Roths, J.B., Davidson, W.F., Langdon, W.Y., Fredrickson, T.N., Hartley, J.W. J. Exp. Med. (1985)