HUMAN HOMOLOGY AND CANDIDATE GENES FOR THE DOMINANT MEGACOLON LOCUS, A MOUSE MODEL OF HIRSCHSPRUNG DISEASE

Hirschsprung disease (HSCR) is a congenital disorder of the enteric ne rvous system characterized by the absence of enteric ganglia. Three ge nes for HSCR have been identified: the RET proto-oncogene, the gene co ding for the endothelin B receptor (EDNRB), and the endothelin 3 gene (EDN3). In mice, natural and in vitro-induced mutations affecting the Ret, Ednrb, and Edn3 genes generate a phenotype similar to human HSCR Another model of HSCR disease is the Dominant megacolon (Dom), a spont aneous mouse mutation for which the target gene has not yet been ident ified. The Dom mutation has been mapped to the middle-terminal region of mouse chromosome 15, between D15Mit68 and D15Mit2. Using new or kno wn polymorphisms for conserved human/mouse genes, we established the h omology between the Dom locus and human chromosome 22q12-q13. Two gene s, Smstr3 and Adsl, not previously mapped in the mouse genome, were lo cated on mouse Chromosome 15. Three genes (Smstr3, Lgals1, and Pdgfb) are possible Dom candidates, as they do not recombine with the Dom mut ation in a 252 Dom/+ animal backcross. (C) 1997 Academic Press