Neuroimaging in Glucocerebrosidase-Associated Parkinsonism: A Systematic Review

Abstract

Background: Mutations in the GBA gene cause Gaucher's disease (GD) and constitute the most frequent genetic risk factor for idiopathic Parkinson's disease (iPD). Nonmanifesting carriers of GBA mutations/variants (GBA-NMC) constitute a potential PD preclinical population, whereas PD patients carrying some GBA mutations/variants (GBA-PD) have a higher risk of a more aggressive disease course. Different neuroimaging techniques are emerging as potential biomarkers in PD and have been used to study GBA-associated parkinsonism. Objective: The aim is to critically review studies applying neuroimaging to GBA-associated parkinsonism. Methods: Literature search was performed using PubMed and EMBASE databases (last search February 7, 2022). Studies reporting neuroimaging findings in GBA-PD, GD with and without parkinsonism, and GBA-NMC were included. Results: Thirty-five studies were included. In longitudinal studies, GBA-PD patients show a more aggressive disease than iPD at both structural magnetic resonance imaging and 123-fluoropropylcarbomethoxyiodophenylnortropane single-photon emission computed tomography. Fluorodeoxyglucose-positron emission tomography and brain perfusion studies reported a greater cortical involvement in GBA-PD compared to iPD. Overall, contrasting evidence is available regarding GBA-NMC for imaging and clinical findings, although subtle differences have been reported compared with healthy controls with no mutations. Conclusions: Although results must be interpreted with caution due to limitations of the studies, in line with previous clinical observations, GBA-PD showed a more aggressive disease progression in neuroimaging longitudinal studies compared to iPD. Cognitive impairment, a “clinical signature” of GBA-PD, seems to find its neuroimaging correlate in the greater cortical burden displayed by these patients as compared to iPD. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.