Sex Differences in a Novel Mouse Model of Spinocerebellar Ataxia Type 1 (SCA1)

Spinocerebellar ataxia type 1 (SCA1) is a rare autosomal dominant inherited neurodegenerative disease caused by the expansion of glutamine (Q)-encoding CAG repeats in the gene ATAXIN1 (ATXN1). Patients with SCA1 suffer from movement and cognitive deficits and severe cerebellar pathology. Previous studies identified sex differences in disease progression in SCA1 patients, but whether these differences are present in mouse models is unclear. Using a battery of behavioral tests, immunohistochemistry of brain slices, and RNA sequencing, we examined sex differences in motor and cognitive performance, cerebellar pathology, and cerebellar gene expression changes in a recently created conditional knock-in mouse model f-ATXN1^146Q expressing human coding regions of ATXN1 with 146 CAG repeats. We found worse motor performance and weight loss accompanied by increased microglial activation and an increase in immune viral response pathways in male f-ATXN1^146Q mice.