Striatonigral involvement in Fabry Disease: A quantitative and volumetric Magnetic Resonance Imaging study

Introduction: Aim of this study is to elucidate possible mechanisms of extrapyramidal damage in Fabry Disease (FD), a condition in which involvement of the motor system has been recently suggested, by simultaneously assessing morphometric and susceptibility changes of striatonigral pathway and their possible correlations with clinical variables. Methods: In this cross-sectional study, we investigated possible differences in terms of Quantitative Susceptibility Mapping (QSM) values and volumes of different extrapyramidal relays, including striatum and substantia nigra (SN), in 30 FD patients (M/F = 11/19, mean age 42.6 ± 12.2) and 37 healthy controls (HC) (M/F = 16/21, mean age 43.2 ± 14.6). Patients underwent a clinical examination for the study of different motor functions, and the relationship between MRI and clinical variables was tested using the Spearman's coefficient. Results: Compared to HC, FD patients showed an increase in susceptibility values of the SN (p < 0.001) and striatum (p = 0.001), while no difference emerged for the other tested extrapyramidal structures, suggesting their relative sparing. The increased susceptibility was coupled to a reduced volume of the SN (p < 0.001), but not of the striatum (p = 0.34). Finally, no significant correlation emerged when probing the relationship between these modifications and the clinical variables. Conclusion: In FD patients, susceptibility and volumetric alterations are present throughout the extrapyramidal pathway, with the SN being particularly affected by these changes. Such results are in line with the subtle extrapyramidal involvement recently suggested in FD, and could further contribute to the understanding of the physiopathological bases of cerebral involvement in FD.