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Phenotypes Associated with This Genotype
Genotype
MGI:2177208
Allelic
Composition
Fxntm2Mkn/Fxntm2.1Mkn
Tg(Eno2-cre)39Jme/0
Genetic
Background
involves: 129 * C57BL/6J
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Fxntm2.1Mkn mutation (0 available); any Fxn mutation (30 available)
Fxntm2Mkn mutation (0 available); any Fxn mutation (30 available)
Tg(Eno2-cre)39Jme mutation (3 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
mortality/aging
• mutant mice die at 24 9 days after birth

behavior/neurological
• mutant mice display loss of proprioception, as shown by the mis-positioning of the right hind-paw, which the mouse fails to perceive
• mutant mice exhibit an average onset of ataxia at 12 days after birth
• mutant mice develop a rapidly progressive gait abnormality

growth/size/body
• mutant mice exhibit a low birth weight
• mutants mice show progressive weight loss, with a 18% and 41% weight reduction noted at 7 days after birth and at death, respectively
• by P16, most mutants are moribund and rapidly stop gaining weight; some even rapidly lose weight
• at P12, mutants display reduced body length relative to wild-type mice; however, no obvious skeletal abnormalities are observed
• mutant mice display reduced growth rates throughout their lifespan relative to wild-type mice

muscle
• at 2 weeks, mutant cardiac muscle contains numerous lipid droplets and giant mitochondria with disorganized cristae

cardiovascular system
• at 2 weeks, mutant cardiac muscle contains numerous lipid droplets and giant mitochondria with disorganized cristae
• at 2-3 weeks of age (shortly before or at death), mutants show a significantly increased mean heart to body weight ratio relative to wild-type mice (13.7 6 mg/g vs 5.8 0.5 mg/g, respectively)

cellular
• at 2 weeks, 50% of cardiac mitochondria appear to be swollen in the myofibrils

nervous system
• mutants exhibit areas of degeneration and necrosis in the dentate nucleus of the cerebellum and the brainstem (esp. in the trigeminal nucleus and tracts, the vestibular system and the cochlear nuclei and nerve)
• in contrast, the spinal cord, dorsal root ganglia and peripheral nerves appear unaffected
• upon electromyography, mutants show specific absence of the spinal somatosensory evoked response (H band), indicating a dysfunction in the large myelinated proprioceptive sensory neurons
• in contrast, the small myelinated sensory axons of the tail (heat and pain) have normal velocity

Mouse Models of Human Disease
DO ID OMIM ID(s) Ref(s)
Friedreich ataxia DOID:12705 OMIM:229300
OMIM:601992
J:75420


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
09/05/2019
MGI 6.14
The Jackson Laboratory