Phenotypes Associated with This Genotype

Genotype
MGI:5532284

• Allelic Composition: Itpr1^tm1.1Kmik/Itpr1^tm1.1Kmik; Tg(Pcp2-cre)2Mpin/0
• Genetic Background: involves: 129S/SvEv * 129S1/Sv * 129X1/SvJ * C57BL/6J

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

mortality/aging

mortality/aging ( J:199800 )

N • born at expected Mendelian ratios

N • survive to adulthood

behavior/neurological

behavior/neurological phenotype ( J:199800 )

N • no seizure-like movements

ataxia ( J:199800 )

• cerebellar ataxia beginning around 6 weeks of age

• worsens over time

abnormal visual pursuit ( J:199800 )

• smaller amplitude of horizontal optico kinetic reflex gain but timing is normal

• no adaptive increase in horizontal optico kinetic reflex gain at 10 weeks after 1 hour of exposure to screen oscillations

nervous system

nervous system phenotype ( J:199800 )

N • cerebellar morphology is more or less normal

N • climbing fiber distribution is normal at 10 weeks of age

N • no abnormal enlargement of parallel fiber presynaptic terminals

abnormal cerebellum morphology ( J:199800 )

abnormal Purkinje cell dendrite morphology ( J:199800 )

• fewer dendritic branching points

• increased spine density in the distal dendritic region

decreased Purkinje cell size ( J:199800 )

• soma is smaller at 10 weeks of age but no degeneration is apparent

thin cerebellar molecular layer ( J:199800 )

• thin at 10 weeks of age

abnormal CNS synaptic transmission ( J:199800 )

abnormal excitatory postsynaptic potential ( J:199800 )

• significantly increased parallel fiber EPSP at 10 weeks of age

absent long-term depression ( J:199800 )

• induction of long term depression by stimulation of parallel fibers and climbing fibers is blocked

• long term depression by direct depolarization of Purkinje cells is blocked

vision/eye

abnormal visual pursuit ( J:199800 )

• smaller amplitude of horizontal optico kinetic reflex gain but timing is normal

• no adaptive increase in horizontal optico kinetic reflex gain at 10 weeks after 1 hour of exposure to screen oscillations