Phenotypes Associated with This Genotype

Genotype
MGI:5315461

• Allelic Composition: Atxn7^tm1Hzo/Atxn7^tm1Hzo; Kat2a^tm3.1Roth/Kat2a⁺
• Genetic Background: involves: 129 * 129S7/SvEvBrd

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

mortality/aging

premature death ( J:179021 )

• average life span of double mutants with 100 CAG repeats in Atxn7 is 10.7 +/- 7.5 months, and none of the mutants survive more than 1 year

behavior/neurological

limb grasping ( J:179021 )

• 66.6% of double mutants with 100 CAG repeats in Atxn7 are unable to stretch out their hindlimbs upon tail suspension and exhibit limb grasping at 6-8 months of age

ataxia ( J:179021 )

• double mutants with 100 CAG repeats in Atxn7 exhibit ataxic gait

abnormal gait ( J:179021 )

• at 8-9 months of age, but not 4 months of age, double mutants with 100 CAG repeats in Atxn7 walk with a significantly wider hind stance and dispersed fore- and hind-steps relative to wild-type mice, indicating an uncoordinated walking gait

• this uncoordinated walking gait is worse in these double mutants with 100 CAG repeats than in single homozygous or heterozygous Atxn7 mice with 100 CAG repeats

• gait of double mutants with 100 CAG repeats deteriorates over time into a severe stagger

nervous system

Purkinje cell degeneration ( J:179021 )

• double mutants with 100 CAG repeats in Atxn7 have fewer Purkinje cells at 9 months of age, but not at 5 months of age, indicating a loss of these cells

• Purkinje cell loss is significantly worse in lobule X of double mutants with 100 CAG repeats in Atxn7 than in other regions

decreased Purkinje cell number ( J:179021 )

• double mutants with 100 CAG repeats in Atxn7 have fewer Purkinje cells at 9 months of age, but not at 5 months of age, indicating a loss of these cells

decreased Purkinje cell size ( J:179021 )

• Purkinje cells of double mutants with 100 CAG repeats in Atxn7 have smaller soma size

abnormal cerebellum vermis morphology ( J:179021 )

• the cerebellar vermis of double mutants with 100 CAG repeats in Atxn7 shows cortical atrophy in the molecular layer of lobules VI, VII, and X at 8-9 months of age; atrophy is more severe in the double mutants than in single Atxn7^tm1Hzo homozygotes with 100 CAG repeats

photoreceptor inner segment degeneration ( J:179021 )

• by 2 months of age, double mutants with 100 CAG repeats in Atxn7 exhibit thinner inner segment layers of the retina, indicating photoreceptor degeneration

photoreceptor outer segment degeneration ( J:179021 )

• by 2 months of age, double mutants with 100 CAG repeats in Atxn7 exhibit thinner outer segment layers of the retina, which is completely gone by 8 months of age, indicating photoreceptor degeneration

retina photoreceptor degeneration ( J:179021 )

• double mutants with 100 CAG repeats in Atxn7 develop retinal atrophy, first observed at 1.5-2 months of age, indicating accelerated retinal degeneration compared to single Atxn7 homozygous mice with 100 CAG repeats

vision/eye

photoreceptor inner segment degeneration ( J:179021 )

• by 2 months of age, double mutants with 100 CAG repeats in Atxn7 exhibit thinner inner segment layers of the retina, indicating photoreceptor degeneration

photoreceptor outer segment degeneration ( J:179021 )

• by 2 months of age, double mutants with 100 CAG repeats in Atxn7 exhibit thinner outer segment layers of the retina, which is completely gone by 8 months of age, indicating photoreceptor degeneration

retina photoreceptor degeneration ( J:179021 )

• double mutants with 100 CAG repeats in Atxn7 develop retinal atrophy, first observed at 1.5-2 months of age, indicating accelerated retinal degeneration compared to single Atxn7 homozygous mice with 100 CAG repeats

thin retina inner nuclear layer ( J:179021 )

• in double mutants with 100 CAG repeats in Atxn7

thin retina outer nuclear layer ( J:179021 )

• in double mutants with 100 CAG repeats in Atxn7

retina outer nuclear layer degeneration ( J:179021 )

• double mutants with 100 CAG repeats in Atxn7 show progressive thinning of the outer nuclear layer and inner nuclear layer at 4 months of age that is drastic my 8 months of age

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
spinocerebellar ataxia type 7		DOID:0050958	OMIM:164500	J:179021