- Linkage, but not gene order, of homologous loci, including alpha-L-iduronidase (Idua), is conserved in the Huntington disease region of the mouse and human genomes. Koizumi, T., MacDonald, M., Búcan, M., Hopwood, J.J., Morris, C.P., Scott, H.S., Gusella, J.F., Nadeau, J.H. Mamm. Genome (1992)