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Phenotypes Associated with This Genotype
Genotype
MGI:3804499
Allelic
Composition
Tnnt2tm2Mmto/Tnnt2+
Genetic
Background
involves: 129S/SvEv * C57BL/6
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Tnnt2tm2Mmto mutation (0 available); any Tnnt2 mutation (39 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
mortality/aging
• high incidence of sudden death in mice particularly between 1 and 3 months of age
• mice die after developing repetitive Torsade des Pointes which degenerates into ventricular defibrillation
• treatment with pimobendan, a Ca2+ sensitizer increases life span

cardiovascular system
• increase in size is greater in homozygotes compared to heterozygotes
• treatment with pimobendan, a Ca2+ sensitizer decreases heart size
• increase in left ventricular end-diastolic dimension
• however, no significant differences in wall thickness are detected
• markers of heart failure are significantly increased at 3 and 5 but not at 2 months of age
• significant reduction in left ventricular ejection fraction
• lower left ventricular end-systolic pressure after administration of isoproterenol
• but, no significant difference in blood pressure of heart rate
• electrophysiological abnormalities with long QT
• decrease in Ca2+ sensitivity of force generation with a reduced pCa value at half-maximal force generation
• faster peak rates of increase and decrease in cytoplasmic Ca2+ in intact fibers compared to wild-type controls
• significant increase in cardiomyocyte apoptosis
• differences are larger in homozygotes compared to heterozygotes
• however, maximum force-generating capabilities and Hill coefficient values are not different from controls and intact fibers show no significant decrease in maximum isometric force per cross-sectional area

muscle
• significant reduction in left ventricular ejection fraction

Mouse Models of Human Disease
DO ID OMIM ID(s) Ref(s)
dilated cardiomyopathy 1D DOID:0110426 OMIM:601494
J:137784


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
06/18/2019
MGI 6.14
The Jackson Laboratory