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Phenotypes Associated with This Genotype
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Fmr1tm1.1Ics mutation (0 available); any Fmr1 mutation (28 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
• in the novel object recognition test, mice spend less time than wild-type mice exploring the novel object and more time sniffing the old object, showing a lower discrimination index
• the time spent sniffing the novel social stimulus and the ability to discriminate between the novel mouse and the empty cage are reduced in males, but not females
• pups removed from the nest show an approximate 50% decrease in the number of ultrasonic vocalizations

nervous system
• cultured hippocampal neurons show an increase in spine density
• hippocampal neurons in the CA1 region show an increase in spine density both in basal and apical dendrites
• however, length of dendritic spines is normal
• the postsynaptic density thickness in hippocampal neurons is reduced
• however, no difference in the length of the postsynaptic densities
• increase in the density of excitatory synapses in the hippocampus
• increase in the density of synaptic vesicles in hippocampal presynaptic termini
• hippocampal plasticity is severely impaired
• induction of long-term potentiation by high-frequency stimulation in the hippocampus is reduced in males; impaired LTP is most likely due to postsynaptic impairments rather than presynaptic alterations as no difference in mean fiber volley slope is seen
• CA1 hippocampal neurons exhibit enhanced amplitude of AMPAR-mediated miniature excitatory postsynaptic currents
• however, no differences in the frequency of mEPSCs or the kinetics of these events are seen

Mouse Models of Human Disease
DO ID OMIM ID(s) Ref(s)
fragile X syndrome DOID:14261 OMIM:300624

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 6.17
The Jackson Laboratory