- Physical and genetic localization of quinonoid dihydropteridine reductase gene (QDPR) on short arm of chromosome 4. MacDonald, M.E., Anderson, M.A., Lockyer, J.L., Milstien, S., Hobbs, W.J., Faryniarz, A.G., Kaufman, S., Ledley, F.D., Woo, S.L., Gusella, J.F. Somat. Cell Mol. Genet. (1987)