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Phenotypes Associated with This Genotype
involves: C57BL/6J * C57BL/6N * SJL/J
Cell Lines EPD0069_2_H11
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Gfpt1tm1c(EUCOMM)Wtsi mutation (1 available); any Gfpt1 mutation (9 available)
Tg(Ckmm-cre)5Khn mutation (4 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
• necrotic skeletal myofibers are observed

• starting at 6 weeks of age, mice show a significant reduction in the latency to fall from a wire grid at various time points up to 6 months of age in the inverted screen test assay
• however, the deficit in motor performance is not progressive over the first 6 months

• no pathological changes are observed in cardiac muscle
• EM revealed the presence of ectopic subsarcolemmal caveolae-like vesicular structures in intercostal muscle, indicating ER-Golgi-stress
• soleus and tibialis anterior (TA) muscles show significantly larger sarcoplasmic caveolin-3 positive punctae than control muscles
• skeletal muscles show occasional rounded myofibers, a small number of fibers with internal nuclei, necrotic fibers, and presence of atrophic and hypertrophic myofibers, some of which exhibit splitting
• tubular aggregates are detected in some myofibers in all muscles examined along with the replacement of myofibers with adipose tissue, esp. in diaphragm muscle
• no differences in the fiber type proportion are observed in the soleus or TA muscles
• no tubular aggregate fiber type specific predominance is observed in the soleus or TA muscles
• necrotic skeletal myofibers are observed
• the intercostal and soleus muscles exhibit a shift towards smaller fibers (29% and 26%, respectively) relative to control muscles
• at 3 months of age, the diaphragm muscle shows muscle fiber atrophy along with a progressive replacement of muscle tissue by fibroadipose tissue
• skeletal muscle fiber hypertrophy is observed; the EDL muscle exhibits a shift towards larger fibers (18%) relative to control muscle
• differences in fiber size are greatest in EDL muscle (61%), followed by the soleus (56%), intercostal (29%) and TA (26%) muscles
• however, median cross-sectional area (CSA) values for TA muscle fiber size remain normal
• a small number of skeletal myofibers have centrally located nuclei
• at 3 months of age, the maximal isometric tetanic force in diaphragm muscle at 150 Hz is reduced by 35.3% relative to that in control mice
• at 3 months of age, a progressive decline in force generated by the TA muscle is evident from 80 tetanic nerve stimulations of the common peroneal nerve (CPN) at 120 Hz (80, 42.9%; 90, 47.7%; 100, 64.7%), whereas a significant (26.1%) reduction of force in control mice is only seen after 100 stimulations compared with baseline
• a progressive reduction in force generated by the diaphragm muscle is noted between 50 and 100 tetanic nerve stimulations at 150 Hz
• at 3 months of age, mice show a progressive increase in TA muscle fatigability, expressed as the % decrease of baseline force, after 80 (20.8%), 90 (26.4%) and 100 (38.7%) tetanic nerve stimulations at 120 Hz relative to control mice
• a progressive increase in diaphragm muscle fatigability is noted between 50 and 100 tetanic nerve stimulations at 150 Hz
• mice exhibit muscle weakness as early as 6 weeks of age
• mice develop progressive myopathic changes in TA, intercostal, soleus, extensor digitorum longus (EDL) and diaphragm muscles

nervous system
• presynaptic alterations in intercostal muscle NMJs include irregular and occasionally convoluted presynaptic myelin sheaths
• the diameter of myelin sheaths is significantly reduced in intercostal muscle
• at 3 months of age, acetylcholine receptor (AChR) clusters in TA, intercostal, soleus and EDL muscles appear smaller and fragmented relative to those in control muscles
• reduction in AChR cluster area is greatest in the TA (45%), followed by the EDL (33%), soleus (28%) and intercostal (27%) muscles
• mean number of fragments/AChR cluster is greatest in the soleus, followed by the EDL, intercostal and TA muscles
• presynaptic changes include discontinuous and disorganized axonal projections, thinner irregular myelin sheaths and remodeling of motor nerve terminals; however, axons can project normally to endplates with no signs of overshooting, retractions or axonal sprouting
• NMJs in intercostal muscle exhibit fewer postsynaptic junctional folds, accumulation of tubular aggregates and subsarcolemmal vesicular structures, deposits of dense filamentous-like material, irregular and convoluted presynaptic myelin sheaths, and a reduction in the diameter of myelin sheaths
• AChR turnover rate in TA muscles is normal

• although mice are slightly smaller than control mice, no significant differences in body weight are observed over the first 6 months

Mouse Models of Human Disease
DO ID OMIM ID(s) Ref(s)
congenital myasthenic syndrome 12 DOID:0110660 OMIM:610542

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
MGI 6.16
The Jackson Laboratory