Phenotypes Associated with This Genotype

Genotype
MGI:5292357

• Allelic Composition: Fmr1^tm1.2Cidz/Y
• Genetic Background: involves: 129P2/OlaHsd * 129/Sv * C57BL/6 * FVB/N

• ♀: phenotype observed in females
• ♂: phenotype observed in males
• N: normal phenotype

nervous system

abnormal hippocampus pyramidal cell morphology ( J:176553 )

♂ • mutants show a lower AMPA to NMDA glutamate receptor ratio in hippocampal CA1 pyramidal neurons at 2 weeks of age, but not at 6-7 weeks of age

abnormal CNS synaptic transmission ( J:176553 )

♂ • mutants show a lower AMPA to NMDA current ratio in hippocampal CA1 neurons at 2 weeks of age, but not at 6-7 weeks of age, indicating that glutamatergic neuerotransmission at synapses of hippocampal CA1 pyramidal neurons is altered during early postnatal development but not in adulthood

enhanced long-term potentiation ( J:176553 )

♂ • induction of NMDA receptor-dependent long-term potentiation following a low-frequency pairing protocol, but not theta-burst pairing protocol, is increased at 2 weeks of age but not in adulthood

♂ • however, presynaptic paired-pulse potentiation in the hippocampal CA1 neurons and intrinsic postsynaptic excitability are unchanged in mutants and no differences in short- and long-term depression are seen

abnormal miniature excitatory postsynaptic currents ( J:176553 )

♂ • miniature currents are altered in mutants; AMPA mEPSCs are reduced in amplitude but not in frequency while NMDA mEPSCs are increased in amplitude

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
fragile X syndrome		DOID:14261	OMIM:300624	J:176553