Objective: Using a semiautomated volumetric MRI assessment method, we aimed to identify determinants of white matter hyperintensity (WMH) burden in patients with Fabry disease (FD).Methods: Patients with confirmed FD and brain MRI available for this analysis were eligible for this protocol after written consent. Clinical characteristics were abstracted from medical records. T2 fluid-attenuated inversion recovery MRI were transferred in electronic format and analyzed for WMH volume (WMHV) using a validated, computer-assisted method. WMHV was normalized for head size (nWMHV) and natural log-transformed (lnWMHV) for univariate and multivariate linear regression analyses. Level of significance was set at p , 0.05 for all analyses.Results: Of 223 patients with FD and WMHV analyzed, 132 (59%) were female. Mean age at MRI was 39.2 6 14.9 (range 9.6-72.7) years, and 136 (61%) patients received enzyme replacement therapy prior to enrollment. Median nWMHV was 2. Cerebrovascular disease, including stroke, is a significant source of morbidity in patients with Fabry disease (FD), an X-linked lysosomal storage disorder characterized by reduced activity of the enzyme a-galactosidase A.1 Burden of MRI-detectable white matter hyperintensity (WMH) has been linked to risk of stroke, 2 poor poststroke outcome, 3 and functional disability in aging adults 4 ; however, there are no systematic studies of WMH in patients with FD. Previously, nonquantitative studies have documented WMH lesions in adults with FD, 5,6 pediatric patients, 7 and the Fabry Outcome Survey registry participants. 8 A comparison of CT and MRI findings in patients with FD suggested the potential utility of a rating scale in this population. 9 The recently published Stroke in Young Fabry Patients (SIFAP1) study 10 showed detailed neuroimaging MRI characteristics including WMH assessed using a validated ordinal scale 11,12 ; however, it failed to identify any FD-specific MRI characteristics.