TY - JOUR T1 - Rapid Onset of Motor Deficits in a Mouse Model of Spinocerebellar Ataxia Type 6 Precedes Late Cerebellar Degeneration JF - eneuro JO - eNeuro DO - 10.1523/ENEURO.0094-15.2015 VL - 2 IS - 6 SP - ENEURO.0094-15.2015 AU - Sriram Jayabal AU - Lovisa Ljungberg AU - Thomas Erwes AU - Alexander Cormier AU - Sabrina Quilez AU - Sara El Jaouhari AU - Alanna J. Watt Y1 - 2015/11/01 UR - http://www.eneuro.org/content/2/6/ENEURO.0094-15.2015.abstract N2 - Spinocerebellar ataxia type 6 (SCA6) is an autosomal-dominant cerebellar ataxia that has been associated with loss of cerebellar Purkinje cells. Disease onset is typically at midlife, although it can vary widely from late teens to old age in SCA6 patients. Our study focused on an SCA6 knock-in mouse model with a hyper-expanded (84X) CAG repeat expansion that displays midlife-onset motor deficits at ∼7 months old, reminiscent of midlife-onset symptoms in SCA6 patients, although a detailed phenotypic analysis of these mice has not yet been reported. Here, we characterize the onset of motor deficits in SCA684Q mice using a battery of behavioral assays to test for impairments in motor coordination, balance, and gait. We found that these mice performed normally on these assays up to and including at 6 months, but motor impairment was detected at 7 months with all motor coordination assays used, suggesting that motor deficits emerge rapidly during a narrow age window in SCA684Q mice. In contrast to what is seen in SCA6 patients, the decrease in motor coordination was observed without alterations in gait. No loss of cerebellar Purkinje cells or striatal neurons were observed at 7 months, the age at which motor deficits were first detected, but significant Purkinje cell loss was observed in 2-year-old SCA684Q mice, arguing that Purkinje cell death does not significantly contribute to the early stages of SCA6. ER -