MAPPING OF THE X-LINKED CATARACT (XCAT) MUTATION, THE GENE IMPLICATEDIN THE NANCE-HORAN-SYNDROME, ON THE MOUSE X-CHROMOSOME

The Xcat mutation in the mouse, an X-linked inherited disorder, is cha racterized by the congenital onset of cataracts. The cataracts have mo rphologies similar to those of cataracts found in the human Nance Hora n (X-linked cataract dental) syndrome, suggesting that Xcat is an anim al model for Nance Horan. The Xcat mutation provides an opportunity to investigate, at the molecular level, the pathogenesis of cataract. As a first step to cloning the Xcat gene, we report the localization of the Xcat mutation with respect to known molecular markers on the mouse X chromosome. Backcross progeny carrying the Xcat mutation were obtai ned from an interspecific cross. Genomic DNA from each mouse was subje cted to Southern and PCR analysis to identify restriction fragment len gth polymorphisms and simple sequence length polymorphisms, respective ly. Our results refine the location of Xcat to a 2-cM region, eliminat e several genes from consideration as the Xcat mutation, identify mole cular probes tightly linked with Xcat, and suggest candidate genes res ponsible for the Xcat phenotype. (C) 1994 Academic Press, Inc.