- Genetic linkage of a polymorphism in the type II procollagen gene (COL2A1) to primary osteoarthritis associated with mild chondrodysplasia. Knowlton, R.G., Katzenstein, P.L., Moskowitz, R.W., Weaver, E.J., Malemud, C.J., Pathria, M.N., Jimenez, S.A., Prockop, D.J. N. Engl. J. Med. (1990)