About   Help   FAQ
Due to maintenance, access to MGI may be intermittent 8:00 AM ET Wed, September 18.
Phenotypes Associated with This Genotype
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
• mutant mice die at 24 9 days after birth

• 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

• 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

• 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)

• 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

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)
Citing These Resources
Funding Information
Warranty Disclaimer & Copyright Notice
Send questions and comments to User Support.
last database update
MGI 6.14
The Jackson Laboratory