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Phenotypes Associated with This Genotype
involves: 129S1/Sv * 129X1/SvJ * C57BL/6J
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Hmx2tm1Tlu mutation (0 available); any Hmx2 mutation (8 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
• approximately 65% of homozygous mutant mice display hyperactivity
• approximately 65% of homozygous mutant mice display head tilting
• approximately 65% of homozygous mutant mice display circling activity

• the mutant otocyst exhibits altered expression of specific inner ear markers in the presumptive sensory epithelium, as well as ectopic gene activation in the prospective fusion plate, indicating a significant alteration in cell fate in the otic epithelium of the pars superior
• as a result of altered cell fate, the otic epithelium fails to communicate properly with the periotic mesenchyme, and inner ear morphogenesis is disrupted
• at E11.5, a reduced rate of cell division is detected in the otic epithelium as well as in the adjacent periotic mesenchyme; at this stage, thinning of the epithelial layer in specific regions of the otic vesicle fails to occur, suggesting that no region in the mutant otocyst has become competent to form a fusion plate
• at E13.5, the presence of a thinned epithelial layer and its detachment from the underlying basement membrane suggest a potential delayed initiation of fusion plate formation; however, the eventual fusion of the apposing walls of the otocyst to form a semicircular duct never takes place
• homozygous mutant mice display significant loss of the three cristae: also, a putative crista marker is present at E10.5, but disappears by E11.5, suggesting that the cristae might be specified initially but fail to develop properly
• as early as E13.5, approximately 70% of homozygous mutant embryos exhibit severe dysgenesis of all three semicircular ducts; the remaining 30% display variable defects in the vestibule between different individuals, and even between the membranous labyrinths of the same homozygous mutant embryos
• homozygous mutant mice display persistence of the primordial vestibular diverticula, a fused utriculosaccular space in which a common macula is formed, as well as a severe loss of epithelial cells (both sensory and nonsensory) in the developing vestibule

nervous system
• no defects are observed in the CNS, as shown by the behavior, beta-galactosidase activity and histology of homozygous mutant mice and embryos

Contributing Projects:
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB), Gene Ontology (GO)
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last database update
MGI 6.14
The Jackson Laboratory