Global and Regional Brain Grey and White Matter Morphometry Alterations in Type 1, 2, and 3 Spinocerebellar Ataxias (SCAs) Patients.

Spinocerebellar ataxias (SCAs) types 1, 2, and 3 are the most common subtypes of SCAs. However, the atrophy patterns of these three subtypes still need to be fully clarified. In this study, a total of 130 genetically confirmed SCA patients (SCA1: n = 16; SCA2: n = 13; symptomatic SCA3: n = 76; pre-symptomatic SCA3: n = 25) along with 65 age- and sex-matched healthy controls (HCs) were enrolled. MR volumetric analysis was used to explore the different atrophied patterns in these three SCA subtypes and the associations between significant morphometry alterations and clinical variables were further analyzed. Compared with HCs, the global brain grey matter (GM) of the three SCA subtypes and white matter (WM) volumes of the SCA2 and SCA3 were significantly reduced. SCA2 had significantly more severe GM volume atrophy than symptomatic SCA3. For local GM and WM volumes, all three subtypes of SCA have significant atrophy in infra- and supratentorial areas than HCs. The pre-symptomatic SCA3 patients had already demonstrated substantial WM atrophy. The SCAs subgroup comparisons showed that compared with symptomatic SCA3, SCA1 and SCA2 demonstrated more severe atrophy in regions of the cerebral and cerebellum, but symptomatic SCA3 had significantly atrophied bilateral lenticular nuclei. Besides, no significant difference was found in the local GM or WM volume between SCA1 and SCA2. Furthermore, some affected GM and WM regions, especially the damaged cerebellar peduncles, showed significant correlations with disease duration and severity in SCA1 and symptomatic SCA3. Our research results indicate differences in MRI brain injury patterns among common SCA subtypes, which might shed light on the deeper understanding of the pathophysiological mechanisms of SCAs.