Seven-year Follow-up of Cerebellar Type 1 Metabotropic Glutamate Receptor Availability in a Family With Spinocerebellar Ataxia Type 19/21.

Imaging of type 1 metabotropic glutamate receptor (mGluR1), predominantly expressed on Purkinje cells, is available using PET. We have demonstrated that cerebellar mGluR1 availability decreases with disease progression in cerebellar ataxia. This study presents longitudinal changes in a mother and her daughter with spinocerebellar ataxia type 19/21, who underwent 2 sessions of mGluR1 PET and MRI scans, 7 years apart. Our findings show that cerebellar mGluR1 availability decreases as ataxia progresses, and that mGluR1 imaging is likely superior to MRI for detecting small changes within the cerebellum. Therefore, mGluR1 imaging may serve as a specific biomarker for monitoring cerebellar function.