Rajbeer Singh Sangha, MD

Fazekas F, Enzinger C, Schmidt R, Grittner U, Giese AK, Hennerici MG, et al. Brain Magnetic Resonance Imaging Findings Fail to Suspect Fabry Disease inYoung Patients With an Acute Cerebrovascular Event. Stroke. 2015

Fabry disease (FD) is a genetic X-linked lysosomal storage disorder in which the patients are deficient of α-galactosidase A. Due to the deficiency of this enzyme, it leads to accumulations of globotriaosylceramide (Gb-3) into the vascular endothelial, neural and renal cells. Systemic manifestations of the disease include effects on the kidneys, cardiac functioning and central nervous system complications all of which occur later in life. Previous abnormalities that have been reported with FD in the brain include extensive white matter changes, cerebral infarctions primarily in the territories supplied by the posterior circulation and dilation of the vertebrobasilar vessels. One of the pathognomonic signs of FD include high signal intensity of the pulvinar thalami on T1-weighted MRI and this can be found in only a quarter of the patients. The authors of this study focused on analyzing MRI data of young stroke patients who had definite or probable FD. 

The SIFAP 1 study prospectively collected clinical, laboratory and radiologic data of 5023 patients (18-55 years) with an acute CVE. Biochemical findings and genetic testing served to diagnose FD in 45 (0.9%) patients and the MRI data was collected and interpreted centrally without knowing the diagnosis and compared between FD and non-FD patients. The authors found that the presence or extent of white matter hyperintensities, infarct localization, vertebrobasilar artery dilatation, T1-signal hyperintensity of the pulvinar thalami or any other MRI finding did not distinguish FD patients from non-FD CVE patients. Furthermore, the high signal intensity seen in the pulvinar thalami was not visualized in any patients with FD and in 6 non-FD patients. 

The authors conduct a well-designed study in which they analyze radiologic findings for patients with FD and subsequently find there are no significant predictors on MRI which could have be utilized to help direct diagnostic workup for patients. Due to the low power of the study, the authors are not able to make definitive conclusions regarding the ability of MRI to predict Fabry’s disease. They do acknowledge that a complete workup (genetic and laboratory testing) and consideration of clinical history is required in order to identify this difficult to diagnose condition. This holds true in the majority of stroke where the clinical exam, history and totality of findings help in arriving to the correct diagnosis, with radiologic imaging serving as an important tool giving surrogate markers of the disease process itself. With better imaging modalities and tools it is possible that these markers will improve in the near future.