Anderson-Fabry Disease Patients Research Articles

Anderson-Fabry disease management: role of the cardiologist.

Anderson-Fabry disease (AFD) is a lysosomal storage disorder characterized by glycolipid accumulation in cardiac cells, associated with a peculiar form of hypertrophic cardiomyopathy (HCM). Up to 1% of patients with a diagnosis of HCM indeed have AFD. With the availability of targeted therapies for sarcomeric HCM and its genocopies, a timely differential diagnosis is essential. Specifically, the therapeutic landscape for AFD is rapidly evolving and offers increasingly effective, disease-modifying treatment options. However, diagnosing AFD may be difficult, particularly in the non-classic phenotype with prominent or isolated cardiac involvement and no systemic red flags. For many AFD patients, the clinical journey from initial clinical manifestations to diagnosis and appropriate treatment remains challenging, due to late recognition or utter neglect. Consequently, late initiation of treatment results in an exacerbation of cardiac involvement, representing the main cause of morbidity and mortality, irrespective of gender. Optimal management of AFD patients requires a dedicated multidisciplinary team, in which the cardiologist plays a decisive role, ranging from the differential diagnosis to the prevention of complications and the evaluation of timing for disease-specific therapies. The present review aims to redefine the role of cardiologists across the main decision nodes in contemporary AFD clinical care and drug discovery.

Electrocardiogram evolution in Anderson-Fabry disease patients during follow-up

Abstract Background Anderson-Fabry disease (AFD) is a rare and progressive X-linked metabolic disorder caused by mutations in alfa galactosidase A gene, which leads to a pathologic, multiorgan, accumulation of ceramides with cytotoxic, proinflammatory and fibrotic effects. Cardiovascular involvement represents one of the main causes of death. Although ECG has proven to be useful for early AFD recognition, little evidence is available on the evolution of ECG alterations during follow-up. Purpose and Methods The aims of the study were to describe ECG changes during a long-term follow up, and to evaluate their association with the progression of cardiac involvement. The presence of interactions between ECG changes and specific AFD therapy (treatment status) were also evaluated. 219 AFD patients from a multicentre cohort underwent 12-lead ECG extensive analysis, transthoracic echocardiography, and complete clinical evaluation. Results After the exclusion of 3 patients with a permanent pacemaker, 5 with poor ECG quality, 2 with only one ECG, and 18 ≤18 years old, 181 AFD patients composed the final cohort (age 46 [IQR 35-58], 36% male, 67% classic phenotype). Treatment status (either enzyme replacement or chaperone molecules) was distributed as follows: chronic therapy for at least one year (24%), specific therapy started during the follow up (39%), no specific therapy (37%). During a median follow up of 62 months (IQR 33-83 months), several ECG parameters showed significant changes: atrial fibrillation detection (p<0.001), PQ interval (p=0.004), left atrial enlargement (p=0.001), a new right bundle branch block (RBBB, p<0.001), QRS interval (p<0.001) and QRS fragmentation (p=0.022), QTcB interval (p=0.001), and negative T waves development (p=0.001) mostly lateral and symmetric (p=0.016). Among these, PQ interval showed a significant interaction with treatment status being significantly altered only in patients in the chronic therapy and no specific therapy groups, being stable in patients who started the specific therapy during the follow up (p for interaction=0.048). In addition, PQ, QRS interval duration, a new RBBB, and a new pathologic QT interval were associated with the evolution of the echocardiographic maximal left ventricular (LV) wall thickness during the follow up on univariable analysis, with the QRS duration losing the statistical significance on multivariable analysis but still showing a trend (p=0.089) toward an association with an increased LV wall thickness. Conclusions In this multicentric cohort of AFD patients, different ECG parameters underwent significant changes during follow-up. Of these, PQ interval duration showed a significant interaction with the specific therapy status in that it did not increase in patients who started the therapy at the begin of the follow up. PQ interval, a new RBBB and pathologic QTc development were also significantly associated with the progression of LV hypertrophy on multivariable analysis.Table 1 and Table 2Figure 1

Clinical study of left ventricular structure and function in patients with Anderson-Fabry disease before and after enzyme replacement therapy.

Cardiac left ventricular hypertrophy (LVH) is the most common manifestation of heart involvement in Anderson-Fabry disease (AFD). Conventional cardiac imaging is not sensitive enough to detect early signs of LVH in AFD. It remains uncertain whether enzyme replacement therapy (ERT) can prevent LVH progression and improve myocardial function. This study aimed to assess the effectiveness of two-dimensional speckle tracking echocardiography (2D-STE) in early detection of cardiac involvement in AFD and monitoring the efficacy of agalsidase alfa and agalsidase beta therapy. Thirteen consecutive AFD patients and 12 healthy controls underwent standard transthoracic 2D, color Doppler, tissue Doppler echocardiography, and 2D strain analysis. Global longitudinal strain (GLS) and global circumferential strain (GCS) were measured. Diastolic strain rate (SR) was extracted. Compared to healthy subjects, AFD patients without LVH showed lower levels of GLS (p < 0.001) and SR (p = 0.01), while there was no difference in GCS (p = 0.82). Following treatment, apical circumferential strain (ACS) showed improvement (p = 0.01). In AFD patients without LVH, there was a decrease in global and segmental LS. Higher plasma Lyso-GL-3 concentrations were associated with elevated ACS values after ERT, indicating that ACS in AFD patients without LVH, albeit normal, is involved in early LV dysfunction.

Sex Differences in Anderson-Fabry Cardiomyopathy: Clinical, Genetic, and Imaging Analysis in Women.

Anderson-Fabry Disease (AFD) is a rare, systemic lysosomal storage disease triggered by mutations in the GLA gene, leading to α-galactosidase A (α-Gal A) deficiency. The disease's X-linked inheritance leads to more severe, early-onset presentations in males, while females exhibit variable, often insidious, manifestations, notably impacting cardiac health. This study aims to examine gender-based AFD cardiac manifestations in correlation with the variant type: classical (CL), late-onset (LO), or variants of uncertain significance (VUS). We analyzed data from 72 AFD patients (53 females, 19 males) referred to the "G. Rodolico" University Hospital, employing enzyme activity measurements, genetic analysis, periodic lyso-Gb3 monitoring, comprehensive medical histories, and advanced cardiac imaging techniques. Statistical analysis was performed using SPSS version 26. Our AFD cohort, with an average age of 45 ± 16.1 years, comprised 12 individuals with hypertrophy (AFD-LVH) and 60 without (AFD-N). Women, representing about 75% of the subjects, were generally older than men (47.2 ± 16.2 vs. 38.8 ± 14.6, p = 0.046). In the female group, 17% had CL variants, 43.3% LO, and 39.6% had VUS, compared to 21.1%, 36.8%, and 31.6% in the male group, respectively. Females exhibited significantly higher α-Gal A values (median 7.9 vs. 1.8 nmol/mL/h, p < 0.001) and lower lyso-Gb3 levels (1.5 [IQR 1.1-1.7] vs. 1.9 [1.5-17.3] nmol/L, p = 0.02). Regarding the NYHA class distribution, 70% of women were in class I and 28% in class II, compared to 84% and 16% of men, respectively. Among women, 7.5% exhibited ventricular arrhythmias (10.5% in men), and 9.4% had atrial fibrillation (10.5% in men). Cardiac MRIs revealed fibrosis in 57% of examined women, compared to 87% of men. Even among patients without LVH, significant differences persisted in α-Gal A and lyso-Gb3 levels (p = 0.003 and 0.04), as well as LVMi (61.5 vs. 77.5 g/sqm, p = 0.008) and GLS values (-20% vs. -17%, p = 0.01). The analysis underscored older age, decreased lyso-Gb3 deposition, reduced hypertrophy, and lesser GLS compromise in females, suggesting later disease onset. Severe cardiac patterns were associated with classic variants, while more nuanced manifestations were noted in those with VUS. Early GLS impairment in males, irrespective of hypertrophy, emphasized the role of subclinical damage in AFD.

Electrocardiogram analysis in Anderson-Fabry disease: a valuable tool for progressive phenotypic expression tracking.

Electrocardiogram (ECG) has proven to be useful for early detection of cardiac involvement in Anderson-Fabry disease (AFD); however, little evidence is available on the association between ECG alterations and the progression of the disease. To perform a cross sectional comparison of ECG abnormalities throughout different left ventricular hypertrophy (LVH) severity subgroups, providing ECG patterns specific of the progressive AFD stages. 189 AFD patients from a multicenter cohort underwent comprehensive ECG analysis, echocardiography, and clinical evaluation. The study cohort (39% males, median age 47 years, 68% classical AFD) was divided into 4 groups according to different degree of left ventricular (LV) thickness: group A ≤ 9 mm (n = 52, 28%); group B 10-14 mm (n = 76, 40%); group C 15-19 mm (n = 46, 24%); group D ≥ 20 mm (n = 15, 8%). The most frequent conduction delay was right bundle branch block (RBBB), incomplete in groups B and C (20%,22%) and complete RBBB in group D (54%, p < 0.001); none of the patients had left bundle branch block (LBBB). Left anterior fascicular block, LVH criteria, negative T waves, ST depression were more common in the advanced stages of the disease (p < 0.001). Summarizing our results, we suggested ECG patterns representative of the different AFD stages as assessed by the increases in LV thickness over time (Central Figure). Patients from group A showed mostly a normal ECG (77%) or minor anomalies like LVH criteria (8%) and delta wave/slurred QR onset + borderline PR (8%). Differently, patients from groups B and C exhibited more heterogeneous ECG patterns: LVH (17%; 7% respectively); LVH + LV strain (9%; 17%); incomplete RBBB + repolarization abnormalities (8%; 9%), more frequently associated with LVH criteria in group C than B (8%; 15%). Finally, patients from group D showed very peculiar ECG patterns, represented by complete RBBB + LVH and repolarization abnormalities (40%), sometimes associated with QRS fragmentation (13%). ECG is a sensitive tool for early identification and long-term monitoring of cardiac involvement in patients with AFD, providing "instantaneous pictures" along the natural history of AFD. Whether ECG changes may be associated with clinical events remains to be determined.

Anderson-Fabry disease cardiomyopathy: an update on epidemiology, diagnostic approach, management and monitoring strategies.

Anderson-Fabry disease (AFD) is an X-linked lysosomal storage disorder caused by deficient activity of the enzyme alpha-galactosidase. While AFD is recognized as a progressive multi-system disorder, infiltrative cardiomyopathy causing a number of cardiovascular manifestations is recognized as an important complication of this disease. AFD affects both men and women, although the clinical presentation typically varies by sex, with men presenting at a younger age with more neurologic and renal phenotype and women developing a later onset variant with more cardiovascular manifestations. AFD is an important cause of increased myocardial wall thickness, and advances in imaging, in particular cardiac magnetic resonance imaging and T1 mapping techniques, have improved the ability to identify this disease non-invasively. Diagnosis is confirmed by the presence of low alpha-galactosidase activity and identification of a mutation in the GLA gene. Enzyme replacement therapy remains the mainstay of disease modifying therapy, with two formulations currently approved. In addition, newer treatments such as oral chaperone therapy are now available for select patients, with a number of other investigational therapies in development. The availability of these therapies has significantly improved outcomes for AFD patients. Improved survival and the availability of multiple agents has presented new clinical dilemmas regarding disease monitoring and surveillance using clinical, imaging and laboratory biomarkers, in addition to improved approaches to managing cardiovascular risk factors and AFD complications. This review will provide an update on clinical recognition and diagnostic approaches including differentiation from other causes of increased ventricular wall thickness, in addition to modern strategies for management and follow-up.

Prevalence of lymphedema among Anderson-Fabry disease patients: A report from the Fabry registry.

Anderson-Fabry disease (AFD) is a rare X-linked lysosomal storage disease due to a genetic variation in the α-galactosidase A (GLA) gene. As a result, the activity of the α-galactosidase A (AGAL-A) enzyme is reduced or absent, which causes sphingolipid deposition within different body parts. AFD typically manifests with cardiovascular, renal, cerebrovascular, and dermatologic involvement. Lymphedema is caused by sphingolipid deposition within lymphatics. Lymphedema can cause intolerable pain and limit daily activities. Very limited data exist on lymphedema in AFD patients. Using data from the Fabry Registry (NCT00196742) with 7671 patients included (44% males and 56% females), we analyzed the prevalence of lymphedema among AFD patients who were ever assessed for lymphedema and studied the age of first reported lymphedema. Additionally, we assessed whether patients received AFD-specific treatment at some point during their clinical course. The data was stratified by gender and phenotype. Our study showed that lymphedema occurred in 16.5% of the Fabry Registry patients who were ever assessed for lymphedema (n = 5487). Male patients when compared to female patient have higher prevalence (21.7% vs 12.7%) and experienced lymphedema at a younger age (median age at first reported lymphedema of 43.7 vs 51.7 years). When compared to other phenotypes, classic phenotype has the highest prevalence of lymphedema with the earliest reported lymphedema. Among those who reported lymphedema, 84.5% received AFD-specific treatment during their clinical course. Lymphedema is a common manifestation of AFD in both genders, with a tendency to present later in female patients. Recognition of lymphedema can offer an important opportunity for intervention and potential impact on associated morbidity. Additional future studies are needed to characterize the clinical implications of lymphedema in AFD patients and identify additional treatment options for this growing population.

Abstract 15660: Impaired Mitochondrial Quality Control Drives the Development of Cardiomyopathy in Anderson-Fabry Disease

Introduction: Anderson-Fabry disease (AFD) is a systemic disorder caused by impaired alpha-galactosidase (GLA) activity, leading to a progressive cardiomyopathy, with hypertrophy and diastolic dysfunction. However, the molecular mechanisms underlying these features are unknown. Aim: To explore the role of mitochondria as a pathogenic mechanism of cardiac dysfunction in AFD. Methods: We tested a transgenic mouse that lacks endogenous GLA and expresses human R301Q-GLA [Tg/GLA knockout]. We performed serial ecochardiographic, histological, and biochemical analyses on cardiac tissue and single cell contractility on isolated adult cardiomyocytes (CM). Moreover, we assessed mitochondrial morphology/function in mouse embryonic fibroblasts (MEFs). Results: AFD-MEFs display an impaired mitochondrial respiration and reduced ATP synthesis. Increased mitochondrial levels of DRP1, LC3II, and MFN-ubiquitination along with accumulation of fragmented mitochondria and autophagosomes indicate the presence of mitophagy-targeted mitochondria that were not removed. Reduced PGC-1a and mitochondrial-DNA synthesis in AFD-MEFs indicate impaired mitochondrial biogenesis as well. Altogether, our data indicate impaired mitophagy and quality control of AFD-mitochondria. At echocardiography, AFD mice showed diastolic dysfunction and hypertrophy starting from 9 months. Isolated AFD-CMs exhibit reduced inotropic response to isoproterenol. Remarkably, alterations of cardiac mitochondrial function were observed starting from 3 months, including increased levels of MFN2-ubiquitination, DRP1 and LC3II, decreased levels of PGC-1a along with accumulation of disarranged mitochondria and autophagosomes. Frank impairment of mitochondrial respiration in AFD-CMs and reduced myocardial ATP-content was detected from 6 months, together with increased release of Cytochrome-C in the cytosol. Strikingly, mitochondrial dysfunction was also detected in fibroblasts isolated from AFD patients, which have a significantly reduced electron transport chain activity. Conclusions: In AFD, energetic alterations associated with impaired autophagy/mitophagy, are evident at 3 months and progressively lead to cardiac hypertrophy and dysfunction.

Electrocardiographic evolution in Anderson-Fabry disease patients on and off specific therapy: a potential marker to study the therapeutic cardiac goal

Abstract Background Anderson Fabry disease (AFD) is an X-linked lysosomal storage disorder leading to a deficiency in α-galactosidase A and globotriasylceramide (Gb3) deposition in different organs, including the heart. In AFD patients electrocardiogram (ECG) represents an important tool to detect cardiac involvement. AFD specific therapy (enzyme replacement or chaperon therapy) has shown to modify the natural history of the disease and to decrease Gb3 levels, but so far there are no data on its influence on ECG evolution. Purpose To assess the progression of ECG features in AFD patients on and off specific disease therapy and to evaluate the potential role of ECG in studying the cardiac specific response to therapy. Methods We recruited 170 patients with an established AFD diagnosis, ≥18 years old (64 males 38%, median age 46±15 years) in a multicentre study cohort. We analysed their ECG evolution for a median follow-up of 64±48 months in patients off (group A, N=63) and on (group B, N=107) specific therapy. Results AFD patients off specific disease therapy (group A) had similar age at baseline compared to those on therapy (47±14 vs 44±12 years; p=0,171), however significantly differed for males prevalence [13 (21%) vs 51 (48%); p≤0,001], classic phenotype [36 (57%) vs 82 (77%); p&amp;lt;0,001)] and maximal wall thickness [11±3 vs 13±4 mm; p≤0,0001]. As regards ECG features at baseline, group A showed a lower prevalence of repolarization anomalies [16 (25%) vs 51 (48%), p=0,005], left ventricular hypertrophy [14 (22%) vs 51 (48%), p=0,001], pseudo necrosis [4 (6%) vs 18 (17%) vs, p≤0,060] and short PR [2 (3%) vs 12 (11%), p=0.0845]. During the follow-up ECG progression was observed in 9 patients in group A (14%), characterized by the development of repolarization anomalies (N=5; 8%), incomplete right bundle block (N=4; 6%), shortening of PR interval (N=2; 3%), left ventricular hypertrophy (N=2; 3%), left atrial enlargement (N=2; 3%) and complete right bundle block (N=1; 2%). Differently, in group B an ECG evolution was observed in 31 patients (29%) characterized by the development of repolarization anomalies (N=19; 18%), left atrial enlargement (N=12; 12%), complete right bundle block (N=8; 8%), left anterior fascicular hemiblock (N=4; 4%), left bundle block (N=4, 4%) and left ventricular hypertrophy (N=3; 3%). Among patients off therapy we observed an improvement of ECG in 1 patient characterized by regression of repolarization anomalies, which could be explained with the presence of transient overload anomalies. Conclusion In AFD patients off and on specific disease therapy, ECG evolution was detected in 14% and 29% respectively, consistently with the more advanced cardiac involvement in patients on therapy (higher prevalence of male sex, classic phenotype and higher maximum wall thickness). The fact that one third of the patients showed ECG changes progression despite being on specific disease therapy could be relevant to better defined the therapeutic cardiac goal. Funding Acknowledgement Type of funding sources: None.

ECG as a storytelling of cardiac involvement evolution in Anderson Fabry disease

Abstract Background Cardiac involvement in Anderson-Fabry disease (AFD) is related to a progressive glycosphingolipid storage over time and is characterized by left ventricular hypertrophy (LVH), conduction abnormalities and myocardial fibrosis. ECG is useful for early recognition of AFD, however evidence is limited on the association between ECG alterations and disease stage. Purpose To assess the relationship between ECG characteristics and progressive cardiac involvement, from the pre-hypertrophic phase to phenotypes with increasing degree of LVH. Methods In a multicenter cohort, 183 AFD patients (40% male, age 47±12 years, 60% affected by “classical AFD”) underwent ECG and transthoracic echocardiography. Patients were divided into 4 groups according to the different degree of LV thickness measured in parasternal short axis view: group A ≤9 mm (N=46, 25%), group B 10–14 mm (N=77, 42%), group C 15–19 mm (N=45, 25%) and group D ≥20 mm (N=15, 8%). Patients with pacemaker and under 18 years of age were excluded. Results A normal ECG was present in 89% in group A, 59% in group B, 11% in group C and it was absent in group D. Short PR (&amp;lt;120 ms) was more frequent in group A, whereas with LVH increasing, median PR interval duration significantly prolonged among the 4 groups (136 [125–150]vs 141 [130–160] vs 160 [130–180] vs 170 [130–180] ms, p=0.002 respectively). Median P-wave duration was shorter in group A and B compared to group C and D (80 m vs 100 ms, p&amp;lt;0.001), while both QRS and QTc gradually increased. Median Sokolow-Lyon voltage criteria statistically augmented among the groups (22 [18–26] vs 27 [20–33] vs 32 [25–45] vs 35 [18–40] mm, p&amp;lt;0.001 respectively), along with right ventricular hypertrophy (0%, 1%, 11%, 8%, p=0.02). Right bundle branch block (RBBB) had a higher frequency in advanced stages (0%, 34%, 34%, 40%, p&amp;lt;0.001), with a prevalence of complete RBBB of 46% in group D. Similarly, left anterior fascicular block (0%, 7%, 18%, 46%, p&amp;lt;0.001) and QRS fragmentation (2%, 11%, 25%, 23%, p=0.009) were more common in advanced stages. No differences were found in left bundle branch block (LBBB), in low QRS voltages or in LV pre-excitation prevalence. According with the wall thickness increase, negative T waves were more frequent in lateral (4%, 21%, 70%, 77%, p&amp;lt;0.001) and inferior leads (6%, 15%, 32%, 46%, p 0.001), as well as their association with ST-T depression (4%, 17%, 64%, 46%, p&amp;lt;0.001). Giant negative T waves were present only in group C and D (16% and 31%) mainly representing a LVH distribution toward the apex. Conclusions ECG is a very useful tool to stage cardiac involvement evolution in AFD. Peculiar ECG characteristics evolve together with LV wall thickness: incomplete and progressively complete RBBB usually associated (preceding or following) LVH and/or typical repolarization abnormalities in inferior or lateral leads and giant negative T waves in the more advanced stages are the most frequent and typical ECG patterns. Funding Acknowledgement Type of funding sources: None.

PO-659-07 SCREENING OF ANDERSON-FABRY DISEASE IN PATIENTS WITH IMPLANTED PERMANENT PACEMAKER

Anderson-Fabry disease (AFD) is an X-linked inherited lysosomal storage disease caused by a defect in the gene encoding lysosomal enzyme α-galactosidase A (GLA). Atrio-ventricular (AV) nodal conduction defects and sinus node dysfunction are common complications of the disease. It is not fully elucidated how frequently AFD is responsible for acquired AV block or sinus node dysfunction and if some AFD patients could manifest primarily with spontaneous bradycardia in general population.

Prevalence and predictors of bradyarrhythmias requiring permanent pacing in patients with Anderson-Fabry disease.

Bradyarrhythmias are an established red flag for storage cardiac conditions including Anderson-Fabry disease (AFD). The prevalence of bradyarrhythmias requiring a pacemaker (PM) and their timing in AFD is unresolved. We evaluated the prevalence and predictors of PM requirement in a large AFD cohort, investigating the occurrence of bradyarrhythmias as initial versus late manifestation. We retrospectively evaluated 82 consecutive AFD patients referred to our multidisciplinary referral center from 1994 to 2020 with a median follow-up of 6.9 years, identifying those requiring pacing. Univariable analysis was performed to identify cardiac features associated with PM implantation. Five of 82 (6%) AFD patients required PM implantation (5/39, i.e., 13% of those with cardiac involvement), always in the context of advanced cardiomyopathy. In none, bradyarrhythmias were the presenting feature. Indications included sick sinus syndrome in three patients, advanced atrioventricular block in two patients. QRS prolongation during follow-up strongly correlated with the onset of bradyarrhythmias. Severe bradyarrhythmias are relatively frequent in patients with AFD cardiomyopathy, but do not represent a mode of presentation, occurring late in the disease course and always in the context of advanced cardiac involvement. Monitoring QRS variations over time may help to identify patients requiring pacing.

Basal Segmental Strain as a Marker of Cardiac Involvement in Anderson-Fabry Disease

Anderson-Fabry disease (AFD), an X-linked genetic disease, can lead to cardiac involvement, manifesting notably as increased left ventricular (LV) wall thickness and myocardial fibrosis in the 4th-5th decade. We sought to evaluate and validate assessment of global and segmental variations in subclinical LV function by 2D speckle tracking in AFD patients versus healthy controls.

Pathogenesis and Molecular Mechanisms of Anderson-Fabry Disease and Possible New Molecular Addressed Therapeutic Strategies.

Anderson–Fabry disease (AFD) is a rare disease with an incidenceof approximately 1:117,000 male births. Lysosomal accumulation of globotriaosylceramide (Gb3) is the element characterizing Fabry disease due to a hereditary deficiency α-galactosidase A (GLA) enzyme. The accumulation of Gb3 causes lysosomal dysfunction that compromises cell signaling pathways. Deposition of sphingolipids occurs in the autonomic nervous system, dorsal root ganglia, kidney epithelial cells, vascular system cells, and myocardial cells, resulting in organ failure. This manuscript will review the molecular pathogenetic pathways involved in Anderson–Fabry disease and in its organ damage. Some studies reported that inhibition of mitochondrial function and energy metabolism plays a significant role in AFD cardiomyopathy and in kidney disease of AFD patients. Furthermore, mitochondrial dysfunction has been reported as linked to the dysregulation of the autophagy–lysosomal pathway which inhibits the mechanistic target of rapamycin kinase (mTOR) mediated control of mitochondrial metabolism in AFD cells. Cerebrovascular complications due to AFD are caused by cerebral micro vessel stenosis. These are caused by wall thickening resulting from the intramural accumulation of glycolipids, luminal occlusion or thrombosis. Other pathogenetic mechanisms involved in organ damage linked to Gb3 accumulation are endocytosis and lysosomal degradation of endothelial calcium-activated intermediate-conductance potassium ion channel 3.1 (KCa3.1) via a clathrin-dependent process. This process represents a crucial event in endothelial dysfunction. Several studies have identified the deacylated form of Gb3, globotriaosylsphingosine (Lyso-Gb3), as the main catabolite that increases in plasma and urine in patients with AFD. The mean concentrations of Gb3 in all organs and plasma of Galactosidase A knockout mice were significantly higher than those of wild-type mice. The distributions of Gb3 isoforms vary from organ to organ. Various Gb3 isoforms were observed mainly in the kidneys, and kidney-specific Gb3 isoforms were hydroxylated. Furthermore, the action of Gb3 on the KCa3.1 channel suggests a possible contribution of this interaction to the Fabry disease process, as this channel is expressed in various cells, including endothelial cells, fibroblasts, smooth muscle cells in proliferation, microglia, and lymphocytes. These molecular pathways could be considered a potential therapeutic target to correct the enzyme in addition to the traditional enzyme replacement therapies (ERT) or drug chaperone therapy.

Role of serial cardiac 18F-FDG PET-MRI in Anderson\u2013Fabry disease: a pilot study

AimWe investigated the value of serial cardiac 18F-FDG PET-MRI in Anderson–Fabry disease (AFD) and the potential relationship of imaging results with FASTEX score.Methods and resultsThirteen AFD patients underwent cardiac 18F-FDG PET-MRI at baseline and follow-up. Coefficient of variation (COV) of FDG uptake and FASTEX score were assessed. At baseline, 9 patients were enzyme replacement therapy (ERT) naïve and 4 patients were under treatment. Two patients presented a FASTEX score of 0 indicating stable disease and did not show any imaging abnormality at baseline and follow-up PET-MRI. Eleven patients had a FASTEX score > 20% indicating disease worsening. Four of these patients without late gadolinium enhancement (LGE) and with normal COV at baseline and follow-up had a FASTEX score of 35%. Three patients without LGE and with abnormal COV at baseline and follow-up had a FASTEX score ranging from 30 to 70%. Three patients with LGE and abnormal COV at baseline and follow-up had a FASTEX score between 35 and 75%. Finally, one patient with LGE and normal COV had a FASTEX score of 100%. Of the 12 patients on ERT at follow-up, FASTEX score was significantly higher in those 4 showing irreversible cardiac injury at baseline compared to 8 with negative LGE (66 ± 24 vs. 32 ± 21, p = 0.03).Conclusion18F-FDG PET-MRI may be effective to monitor cardiac involvement in AFD.

Standard ECG for differential diagnosis between Anderson-Fabry disease and hypertrophic cardiomyopathy

ObjectivesTo evaluate the role of the ECG in the differential diagnosis between Anderson-Fabry disease (AFD) and hypertrophic cardiomyopathy (HCM).MethodsIn this multicentre retrospective study, 111 AFD patients with left ventricular hypertrophy...

Screening of Fabry Disease in Patients with Chest Pain Without Obstructive Coronary Artery Disease.

Identification of Anderson-Fabry disease (AFD) in cardiac patients has been restricted so far to patients with left ventricular hypertrophy. Coronary microvascular dysfunction has been described in AFD with and without cardiac hypertrophy and may represent the only manifestation in AFD patients, offering a possible earlier diagnosis. We studied the prevalence of AFD in 663 patients with chest pain with normal or non-obstructive coronary arteries. The overall prevalence of AFD in this cohort was only 0.15% (1/663). AFD is not a frequent cause of chest pain without obstructive coronary artery disease and screening efforts should not be conducted in this patient population.

Association between Left Atrial Deformation and Brain Involvement in Patients with Anderson-Fabry Disease at Diagnosis.

Background: Anderson-Fabry disease (AFD) can induce both central nervous system white matter lesions (WMLs) and cardiac abnormalities including left atrial (LA) dysfunction. We sought to evaluate the possible interrelations of LA structure and function impairment with the presence of WMLs in AFD patients. Methods 22 AFD patients and 22 controls, matched for age and sex, underwent an echo-Doppler exam including quantification of peak atrial longitudinal strain (PALS). AFD patients underwent also a 3-T brain magnetic resonance imaging with a visual quantification of WMLs by Fazekas’ score (FS) on 3D FLAIR images. Results AFD patients had significantly higher left ventricular (LV) mass index (LVMi) and relative wall thickness, and lower PALS compared to controls. Among AFD patients, 9 showed a FS = 0, and 13 a FS > 1. AFD patients with FS ≥ 1 showed lower PALS (29.4 ± 6.7 vs. 37.2 ± 3.9%, p = 0.003) than those with FS = 0, without difference in LA volume index and LVMi. In AFD patients, FS was inversely related to PALS (r = −0.49, p < 0.0001), even after adjusting for LVMi (r = −0.43, p < 0.05). Conclusions In the absence of significant alterations in LA size, AFD patients had lower PALS compared to controls. The inverse association between PALS and presence of WMLs indicates a possible parallel early involvement of heart and brain.

Prognostic significance of right ventricular hypertrophy and systolic function in Anderson-Fabry disease.

AimsRight ventricular hypertrophy (RVH) is a common finding in Anderson–Fabry disease (AFD), but the prognostic role of right ventricular (RV) involvement has never been assessed. The aim of our study was to evaluate the prognostic significance of RVH and RV systolic function in AFD.Methods and resultsForty‐five AFD patients (56% male patients) with extensive baseline evaluation, including assessment of RVH and RV systolic function, were followed‐up for an average of 51.2 ± 11.4 months. RV systolic function was assessed by standard and tissue Doppler echocardiography. Cardiovascular events were defined as new‐onset atrial fibrillation (AF), sustained ventricular arrhythmias, heart failure, or pacemaker/implantable cardioverter defibrillator implantation; renal events were defined as progression to dialysis and/or renal transplantation or significant worsening of glomerular filtration rate; and cerebrovascular events were defined as transient ischaemic attack or stroke.Fourteen patients (31.1%) presented RVH, while RV systolic function was normal in all cases. During the follow‐up period, 13 patients (28.8%, 11 male) experienced 18 major events, including two deaths. Cardiovascular events occurred in eight patients (17.7%). The most common event was pacemaker/implantable cardioverter defibrillator implantation (six patients, 13.3%), followed by AF (three cases, 6.6%). Only one case of worsening New York Heart Association class (from II to III and IV) was observed. Ischaemic stroke occurred in three cases (6.6%). Renal events were recorded in three patients (6.6%). At univariate analysis, several variables were associated with the occurrence of events, including RVH (HR: 7.09, 95% CI: 2.17 to 23.14, P = 0.001) and indexes of RV systolic function (tricuspid annular plane systolic excursion HR: 0.77, 95% CI: 0.62 to 0.96, P = 0.02; and RV tissue Doppler systolic velocity HR: 0.76, 95% CI: 0.61 to 0.93, P = 0.01). At multivariate analysis, proteinuria (HR:8.3, 95% CI: 2.88 to 23.87, P < 0.001) and left ventricular mass index (HR: 1.02, 95% CI: 1.00 to 1.03, P = 0.03) emerged as the only independent predictors of outcome.ConclusionsRVH and RV systolic function show significant association with clinical events in AFD, but only proteinuria and left ventricular mass index emerged as independent predictors of outcome. Our findings suggest that RV involvement does not influence prognosis in AFD and confirm that renal involvement and left ventricular hypertrophy are the main determinant of major cardiac and non‐cardiac events.

Left ventricular radial strain impairment precedes hypertrophy in Anderson-Fabry disease.

In Anderson-Fabry disease (AFD), left ventricular (LV) radial function has been scarcely investigated. We hypothesized that LV function may be affected by disease specific mechanisms and sought to comprehensively evaluate LV radial, circumferential and longitudinal function in a large population of AFD patients looking at the influence of LV geometry and fibrosis. We prospectively studied 94 consecutive AFD patients (41.5 ± 14.5 years; 41 men) with preserved LV ejection fraction (EF) utilizing speckle-tracking echocardiography. A subset of patients underwent gadolinium-enhanced cardiac magnetic resonance. Cases were compared to 48 healthy subjects matched for age and sex. LV concentric hypertrophy was found in 33 AFD patients while LV concentric remodeling (relative wall thickness ≥ 0.43) in 16 out 61 patients with normal LV mass. AFD patients had lower radial, longitudinal and circumferential strains than controls, independently by LV geometry pattern. Patients with LV hypertrophy showed reduced global longitudinal strain (p < 0.001) and early diastolic untwisting rate (p = 0.002) as compared to patients with normal geometry. In the whole AFD population, neither radial strain nor circumferential strain correlated with LV mass, while global longitudinal strain and early diastolic untwisting rate did (both p < 0.001). Late gadolinium enhancement was significantly associated with longitudinal strain, twisting rate and early diastolic untwisting rate, with twisting rate being the most powerful independent predictor (β = - 0.461; p = 0.002). Findings demonstrate impairment of LV radial strain in AFD patients with preserved EF, even in a pre-hypertrophic stage. Development of LV hypertrophy and fibrosis make worse mostly longitudinal dysfunction.