The LEC rat is an authentic model of human Wilson's disease (WD) with an autosomal recessively inherited hepatitis. We investigated linkage between the hepatitis gene (hts) and the rat retinoblastoma gene (RB), that is closely linked to the WD gene in humans, to see whether or not the hts gene is located on the syntenic region of WD and is the counterpart of the WD gene. Polymerase chain reaction-single strand conformation polymorphism analysis with backcross progenies from LEC and TM strains showed that the recombination rate between these two loci was 55.6%, demonstrating that the hts and RB genes are not linked to each other. These data indicate that the hts gene is not the counterpart of the WD gene and that the human syntenic region on which the WD locus and human RB gene are located, is not conserved in the rat genome.