Analysis Tools
behavior/neurological
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• limp hindpaws due to a failure to dorsiflex at the ankle
• at rest, mice leave their hind limbs extended behind their bodies rather than bringing them under their haunches
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• mice exhibit an abnormal gait characterized by dragging of hindlimbs and supporting themselves on the hind knuckles rather than soles
• gait defects are evident from birth
• however, mice perform well on the rotarod and beam walking assays
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cellular
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• many motor neurons have highly aggregated mitochondria that cluster along the axon
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growth/size/body
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• 15% reduction in body weight at weaning (P20)
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limbs/digits/tail
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• mice often have clenched hindpaws due to an inability to spread the toes
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• hindlimb defects are incompletely penetrant, with 60% bilaterally affected, 26% unilaterally affected, and 14% unaffected
• hindlimb defects are evident from birth
• however, no defect is seen in the forelimbs
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• tails are severely deformed
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short tail
(
J:132035
)
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• mice have drastically shorter tails that are severely deformed
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muscle
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• mice exhibit dramatically reduced anterior musculature of the lower leg
• however, the posterior calf muscle mass is normal
• mice with asymptomatic hindlimbs have an intermediate, variable mass of anterior muscle
• foot muscles are smaller in size
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• severe weakness of the distal hindlimb muscles
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nervous system
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• motor roots have fewer motor axons
• lumbar motor roots are smaller
• motor roots at L4 and L5 contain about 40% fewer axons compared to controls
• loss of motor axons is most severe in the small caliber axons
• however, no reduction in the number of axons in sensory roots is seen
• many motor neurons show improper mitochondrial distribution, with tight clusters of mitochondria within axons
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Mouse Models of Human Disease |
DO ID | OMIM ID(s) | Ref(s) | |
| Charcot-Marie-Tooth disease type 2A2A | DOID:0110155 |
OMIM:609260 |
J:132035 | |
