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Phenotypes Associated with This Genotype
Not Specified
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Chattm1.1Jrs mutation (0 available); any Chat mutation (19 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
• homozygous pups die at birth without ever moving

• at birth mutants display palmar flexion of the front paws characteristic of flaccid paralysis

• at E13.5 muscles are thinner compared to littermate controls
• at E13.5 the number of acetylcholine receptor clusters rich processes extending from myotubes is increased and some of these processes are longer and more branched, however myotubes appear normal by E15 ? E16
• at E16 the liver has herniated through the tendinous center of the diaphragm in greater than 85% of mutants
• at E13.5 fewer fibers are seen in the diaphragm and by E17.5 degenerating myotubes are seen interspersed with viable myotubes

• at birth pups have a hunched back

nervous system
• the number of Schwann cells is also increased in mutant nerves
• the number of axons entering individual endplates and the number sprouting beyond the endplate is increased in mutants
• many myotubes are innervated at multiple sites
• the number of motorneurons is increased by 79% in mutants
• increased branching of intramuscular nerves is accompanied by altered synapses in which the endplate band is twice as wide as normal
• the number of junctional folds is decreased by about 60% in mutants
• the density of acetylcholine receptor clusters is decreased however the size of the clusters was increased by 89% and 69% at E17.5 and E19, respectively
• the diameter of the phrenic nerve is increased in mutants by E13.5
• the number of axons in the phrenic nerve is more than double that in littermate controls
• beginning at E13 in the intramuscular portion of the nerve there is a dramatic excess of secondary branching resulting in the nerve covering more of the muscle's width

Mouse Models of Human Disease
DO ID OMIM ID(s) Ref(s)
congenital myasthenic syndrome 6 DOID:0110671 OMIM:254210

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