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Phenotypes Associated with This Genotype
involves: 129T1/Sv * C57BL/6
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Mtm1tm1.1Jman mutation (0 available); any Mtm1 mutation (17 available)
phenotype observed in females
phenotype observed in males
N normal phenotype

Clinical evaluation of muscle weakness in Mtm1tm1.1Jman/Y mice

• hemizygous males are underrepresented ( 16.6% instead of the expected 25%) suggesting a certain degree of pre- or neonatal lethality, however no time of death was reported
• occurs at 59 +/- 19 days due to cachexia and respiratory insufficiency (J:81791)

• before death
• a progressive growth impairment compared to wild-type littermates reaching a 35% reduction of body weight by 57 days

• a progressive motor deficit
• a decreased muscular strength starting in the hindlimbs at 4-5 weeks
• hindlimbs become completely paralyzed by 8 weeks

• altered emplacement of mitochondria
• myofibrillar disorganization with sarcomeric disarray and Z-ine streaming that may originated from ER dilations
• atrophy and loss of myofibrils
• frequently seen vacuoles do not contain cellular debris as observed in autophagic vacuoles
• a progressive amyotrophy
• presence of an abnormal central, peripheral, or anarchical pattern of oxidative enzyme activity in myofibers
• skeletal muscle demonstrated a generalized myopathy with fiber size variation, hypotrophy, and progressive accumulation of paracentral or central nuclei
• myogenesis is not delayed
• inflammatory infiltrates and fibrosis, generally present in dystrophic muscle, were absent
• neither necrotic nor apoptotic muscle fibers were seen

• by 5-7 weeks

respiratory system
• by 8 weeks

Contributing Projects:
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Tumor Biology (MTB), Gene Ontology (GO), MouseCyc
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last database update
MGI 6.13
The Jackson Laboratory