Giuseppe Pontillo

Cerebellar lobule atrophy and disability in progressive MS

Objective To investigate global and lobular cerebellar volumetries in patients with progressive multiple sclerosis (MS), testing the contribution of cerebellar lobular atrophy to both motor and cognitive performances. Methods Eighty-two patients with progressive MS and 46 healthy controls (HC) were enrolled in this cross-sectional study. Clinical evaluation included motor and cognitive testing: Expanded Disability Status Scale, cerebellar Functional System score, Timed 25-Foot Walk Test, 9-Hole Peg Test (9-HPT), Symbol Digit Modalities Test (SDMT), Brief Visuospatial Memory Test–Revised (BVMT) and California Verbal Learning Test II (CVLT). Cerebellar volumes were automatically obtained using the Spatially Unbiased Infratentorial Toolbox. A hierarchical multiple linear regression analysis was performed to assess the relationship between MRI variables of supratentorial and cerebellar damage (grey matter fraction, T2 lesion volume, metrics of cerebellar atrophy and cerebellar lesion volume) and motor/cognitive scores. Results Patients with MS exhibited lower cerebellar volumes compared with HC. Regression analysis showed that cerebellar metrics accounted for extra variance in both motor and cognitive performances, with cerebellar lesion volume, cerebellar Lobules VI, Crus I and VIIIa atrophy being independent predictors of 9-HPT, SDMT, BVMT and CVLT performances. Conclusions Atrophy of specific cerebellar lobules explains different aspects of motor and cognitive disability in patients with progressive MS. Investigation of cerebellar involvement provides further insight into the pathophysiological basis of clinical disability in progressive MS.

Default mode network modifications in Fabry disease: A resting-state fMRI study with structural correlations

Aim of the study was to evaluate the presence of Default Mode Network (DMN) modifications in Fabry Disease (FD), and their possible correlations with structural alterations and neuropsychological scores. Thirty‐two FD patients with a genetically confirmed diagnosis of classical FD (12 males, mean age 43.3 ± 12.2) were enrolled, along with 35 healthy controls (HC) of comparable age and sex (14 males, mean age 42.1 ± 14.5). Resting‐State fMRI data were analyzed using a seed‐based approach, with six different seeds sampling the main hubs of the DMN. Structural modifications were assessed by means of Voxel‐Based Morphometry (VBM) and Tract‐Based Spatial Statistics analyses. Between‐group differences and correlations with neuropsychological variables were probed voxelwise over the whole brain. Possible correlations between FC modifications and global measures of microstructural alteration were also tested in FD patients with a partial correlation analysis. In the FD group, clusters of increased functional connectivity involving both supratentorial and infratentorial regions emerged, partially correlated to the widespread white matter (WM) damage found in these patients. No gray matter volume differences were found at VBM between the two groups. The connectivity between right inferior frontal gyrus and precuneus was significantly correlated with the Corsi block‐tapping test results (p = .0001). Widespread DMN changes are present in FD patients that correlate with WM alterations and cognitive performance. Our results confirm the current view of a cerebral involvement in FD patients not simply associated to major cerebrovascular events, but also related to significant and diffuse microstructural and functional changes.

Corpus callosum involvement: a useful clue for differentiating Fabry Disease from Multiple Sclerosis

PurposeMultiple sclerosis (MS) has been proposed as a possible differential diagnosis for Fabry disease (FD). The aim of this work was to evaluate the involvement of corpus callosum (CC) on MR images and its possible role as a radiological sign to differentiate between FD and MS.MethodsIn this multicentric study, we retrospectively evaluated the presence of white matter lesions (WMLs) on the FLAIR images of 104 patients with FD and 117 patients with MS. The incidence of CC-WML was assessed in the two groups and also in a subgroup of 37 FD patients showing neurological symptoms.ResultsWMLs were detected in 50 of 104 FD patients (48.1%) and in all MS patients. However, a lesion in the CC was detected in only 3 FD patients (2.9%) and in 106 MS patients (90.6%). In the FD subgroup with neurological symptoms, WMLs were present in 26 of 37 patients (70.3%), with two subjects (5.4%) showing a definite callosal lesion.ConclusionFD patients have a very low incidence of CC involvement on conventional MR images compared to MS, independently from the clinical presentation and the overall degree of WM involvement. Evaluating the presence of CC lesions on brain MR scans can be used as a radiological sign for a differential diagnosis between MS and FD, rapidly addressing the physician toward a correct diagnosis and subsequent treatment options.

Motor involvement in Fabry disease

We have read with great interest the article published by Wise and colleagues on the last issue of Molecular Genetics and Metabolism Reports [1]. The Authors performed a survey study investigating the prevalence of Parkinson Disease (PD) in individuals affected by Fabry Disease (FD), and found that 2 patients out of 90 (2.2%) were diagnosed with PD. Although considering all the limitations of their study design, the Authors conclude that there might be an increased risk of developing PD in individuals with α-galactosidase A mutations. The present work is not the first study exploring and suggesting a possible motor involvement in FD. Indeed, as reported in the manuscript, the presence of subtle motor symptoms in FD, with slower gait and transfer speed, poorer fine manual dexterity and lower hand speed, has been reported [2]. In line with these evidences, both electrophysiology and advanced MRI studies showed an involvement of the primary motor cortex in this condition. In particular, with transcranial magnetic stimulation an increase of excitatory neurotransmission in motor cortex circuits of FD patients was found [3], while a reduction of the functional connectivity between motor cortices and both basal ganglia and cerebellum was proved by a resting-state functional MRI study, resembling findings present in early phases of PD [4]. Finally, pathology studies demonstrated the presence of abnormal globotriaosylceramide accumulation in the substantia nigra of FD patients, a central hub of the basal ganglia motor circuit [5]. We think that all these evidences, together with the results of this study, further support the hypothesis of a possible extrapyramidal involvement in FD. However, only future prospective studies, conducted on large samples of FD patients with the integration of different modalities, as well as a direct comparisons between FD and PD patients, can further confirm or dismiss this pathophysiological hypothesis.

Brain Susceptibility Changes in a Patient with Natalizumab-Related Progressive Multifocal Leukoencephalopathy: A Longitudinal Quantitative Susceptibility Mapping and Relaxometry Study

Background Brain MRI plays an essential role in both diagnosis and follow-up of the JC virus infection of the brain. Recently, MR studies with susceptibility-weighted imaging (SWI) sequences have shown hypointensities in U-fibers adjacent to white matter (WM) lesions of progressive multifocal leukoencephalopathy (PML). This finding has been confirmed with the use of quantitative susceptibility mapping (QSM), allowing to hypothesize a paramagnetic effect in these regions. Here, we report the first longitudinal assessment of QSM and R2* maps in natalizumab-associated PML to evaluate serial changes in susceptibility contrast images and their role in PML diagnosis and follow-up. Case presentation We report the case of a 42-year-old woman with multiple sclerosis (MS) who eventually developed, after the 28th natalizumab infusion, subacute cognitive decline and received a laboratory-confirmed diagnosis of PML, leading to immediate drug discontinuation. Three months later, she suffered a new clinical exacerbation, with a brain scan revealing significant inflammatory activity compatible with the radiological diagnosis of an Immune Reconstitution Inflammatory Syndrome (IRIS). She was then treated with corticosteroids until the clinico-radiological spectrum became stable, with the final outcome of a severe functional impairment. Quantitative maps obtained in the early symptomatic stage clearly showed increased QSM and R2* values in the juxtacortical WM adjacent to PML lesions, which persisted during the subsequent disease course. Discussion and conclusion High QSM and R2* values in U-fibers adjacent to WM lesions were early and seemingly time-independent radiological findings in the presented PML case. This, coupled to the known absence of significant paramagnetic effect of new active MS lesions, could support the use of quantitative MRI as an additional tool in the diagnosis and follow-up of natalizumab-related PML in MS.

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 Spearmans 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.

Multiple sclerosis and fabry Disease, two sides of the coin? The case of an Italian family

BACKGROUND Multiple Sclerosis (MS) is considered among possible differential diagnosis of Fabry Disease (FD), especially in early stages when findings are suggestive but not diagnostic for MS. We report the case of a family in which FD and MS coexist, offering an overview on clues for differential diagnosis and speculating on shared etiopathogenic mechanisms for these conditions. METHODS Taking as starting point the diagnosis of FD in a dialysis patient during a screening programme, we retrospectively rebuilt his family history and revised clinical and imaging examinations of his five siblings, two of which with previous diagnosis of MS. RESULTS After genetic testing, two subjects were found positive to a new α-galactosidase A mutation, probably causative for FD classical variant. The two subjects meeting diagnostic criteria for MS were found negative to any GLA gene mutation, therefore initial diagnosis was confirmed. The remaining two siblings resulted unaffected, with neither clinical nor instrumental evidence of FD and MS. CONCLUSIONS Differential diagnosis between FD and MS may be challenging, especially in early clinical stages when only extensive clinical evaluation and correct MRI interpretation may reduce the risk of misdiagnosis. Moreover this report allows speculating on potential etiological and pathogenic mechanisms, common both to FD and MS.

Reduced Intracranial Volume in Fabry Disease: Evidence of Abnormal Neurodevelopment?

Introduction: Lysosomal storage disorders (LSD) are often characterized by abnormal brain development, reflected by a reduction of intracranial volume (ICV). The aim of our study was to perform a volumetric analysis of intracranial tissues in Fabry Disease (FD), investigating possible reductions of ICV as a potential expression of abnormal brain development in this condition. Materials and Methods: Forty-two FD patients (15 males, mean age 43.3 ± 13.0 years) were enrolled along with 38 healthy controls (HC) of comparable age and sex. Volumetric MRI data were segmented using SPM12 to obtain intracranial tissue volumes, from which ICV values were derived. Results: Mean ICV of FD patients was 8.1% smaller compared to the control group (p < 5·10−5). Unlike what typically happens in neurodegenerative disorders, no significant differences emerged when comparing between the two groups the fractional volumes of gray matter, white matter and CSF (i.e., normalized by ICV), consistent with a harmonious volumetric reduction of intracranial structures. Discussion: The present results suggest that in FD patients an abnormality of brain development is present, expanding the current knowledge about central nervous system involvement in FD, further emphasizing the importance of an early diagnosis.

Absence of infratentorial lesions in Fabry disease contributes to differential diagnosis with multiple sclerosis

Abstract Background and Purpose Multiple Sclerosis (MS) has been proposed as a possible differential diagnosis with Fabry Disease (FD). We evaluated the incidence of infratentorial lesions in FD patients, investigating whether their presence could help in differentiating these two conditions. We explored the diagnostic accuracy of this sign alone and in combination to the involvement of corpus callosum (CC). Methods White Matter lesions were retrospectively evaluated on FLAIR images available from 136 MS and 144 FD patients. Infratentorial involvement was assessed considering the whole cerebellum, and the part of the brainstem included between the occipital foramen and the upper edge of the red nucleus. Furthermore, the presence of callosal lesions was also recorded, evaluating the portion of CC included between the two external walls of the lateral ventricles. Results Infratentorial involvement was detectable in 119/136 (87.5%) MS patients, while it was present in only 17/144 (11.8%) FD patients. When the diagnostic performance of a positive infratentorial involvement was evaluated in combination with the presence of CC lesions, a specificity of 97%, with a positive predictive value of 96% was reached. Conclusions We concluded that the absence of infratentorial lesions, especially when combined to the evaluation of other typical imaging features, can help in the differential diagnosis between MS and FD.