Phenotypes Associated with This Genotype

Genotype
MGI:3774931

• Allelic Composition: Atxn1^tm1Hzo/Atxn1⁺
• Genetic Background: involves: 129S7/SvEvBrd * C57BL/6

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

mortality/aging

premature death ( J:77225 )

• premature death first occurs between 35 to 45 weeks of age

• none of the mice survive past 50 weeks of age

growth/size/body

slow postnatal weight gain ( J:77225 )

• growth retardation starts at 8 weeks of age

• mice weigh 20% less than wild-type littermates by 11 weeks of age

cachexia ( J:77225 )

• mice start losing weight after 20 weeks of age

behavior/neurological

abnormal cued conditioning behavior ( J:77225 )

• in a context fear test, mice display significantly less freezing to the conditioned stimulus 24 hours after the training period but not 1 hour after

abnormal spatial learning ( J:77225 )

• 7-8 week old mice take more time and swim further to locate a submerged but visible platform in a morris water test during the first 6 trials

• mice perform as wells as wild-type controls in later trials

• 7-8 week old mice take more time and swim further to locate a hidden platform in a morris water test regardless of trial number

limb grasping ( J:77225 )

• mice have a clasping phenotype when lifted by the tail starting at 9 weeks of age

ataxia ( J:77225 )

• evident by 20 weeks of age

impaired coordination ( J:77225 )

• retention time in a rotarod test is impaired by about half for both 5 and 7 week old mice

abnormal gait ( J:77225 )

• evident by 20 weeks of age

nervous system

decreased brain weight ( J:77225 )

• brain weight is significantly reduced by 16 weeks of age

dilated brain ventricle ( J:77225 )

• all ventricles are dilated by 40 weeks of age

abnormal Purkinje cell dendrite morphology ( J:77225 )

• there is a reduction in dendritic arbor of cerebellar Purkinje neurons from mice 6 to 11 weeks of age

• this reduction in dendritic arbor leads to a reduction in membrane capacitance

decreased Purkinje cell number ( J:77225 )

• significantly fewer Purkinje cells are present in 40-week old mice compared to wild-type littermates

neuronal intranuclear inclusions ( J:77225 )

• ubiquitinated neuronal intranuclear inclusions (NI) are present in CA1 hippocampal neurons by 7 weeks of age

• NI are also present in cortical neurons and thalamic nuclei by 7 weeks of age

• NI are present in numerous parts of the brain during the endstage of disease

abnormal excitatory postsynaptic potential ( J:77225 )

• EPSP magnitude is significantly decreased in the hippocampus 90 minutes after high-frequency stimulation

reduced long-term potentiation ( J:77225 )

• hippocampus LTP is significantly reduced in 24 week old mice

muscle

muscle degeneration ( J:77225 )

• muscle wasting is evident by 20 weeks of age

• atrophy of lower limb muscles occurs by 30 weeks of age

skeleton

kyphosis ( J:77225 )

• is observed by 30 weeks of age

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
spinocerebellar ataxia type 1		DOID:0050954	OMIM:164400	J:77225