Fabry Disease Rat Model Develops Age- and Sex-Dependent Anterior Segment Ocular Abnormalities.

Purpose: Fabry disease is an X-linked lysosomal storage disorder that results in multi-systemic renal, cardiovascular, and neuropathological damage, including in the eyes. We evaluated anterior segment ocular abnormalities based on age, sex (male and female), and genotype (wild-type, knockout [KO] male, heterozygous [HET] female, and KO female) in a rat model of Fabry disease. Methods: The α-Gal A KO and WT rats were divided into young (6-24 weeks), adult (25-60 weeks), and aged (61+ weeks) groups. Intraocular pressure (IOP) was measured. Eyes were clinically scored for corneal and lens opacity as well as evaluated for corneal epithelial integrity and tear break-up time (TBUT). Anterior chamber depth (ACD) and central corneal thickness (CCT) using anterior segment-optical coherence tomography (AS-OCT). Results: The Fabry rats showed an age-dependent increase in IOP, predominantly in the male genotype. TBUT was decreased in both male and female groups with aging. Epithelial integrity was defective in KO males and HET females with age. However, it was highly compromised in KO females irrespective of age. Corneal and lens opacities were severely affected irrespective of sex or genotype in the aging Fabry rats. AS-OCT quantification of CCT and ACD also demonstrated age-dependent increases but were more pronounced in Fabry versus WT genotypes. Conclusions: Epithelial integrity, corneal, and lens opacities worsened in Fabry rats, whereas IOP and TBUT changes were age-dependent. Similarly, CCT and ACD were age-related but more pronounced in Fabry rats, providing newer insights into the anterior segment ocular abnormalities with age, sex, and genotype in a rat model of Fabry disease.

Inflammation, Oxidative Stress, and Endothelial Dysfunction in the Pathogenesis of Vascular Damage: Unraveling Novel Cardiovascular Risk Factors in Fabry Disease.

Anderson-Fabry disease (AFD), a genetic disorder caused by mutations in the α-galactosidase-A (GLA) gene, disrupts lysosomal function, leading to vascular complications. The accumulation of globotriaosylceramide (Gb3) in arterial walls triggers upregulation of adhesion molecules, decreases endothelial nitric oxide synthesis, and induces reactive oxygen species production. This cascade results in fibrotic thickening, endothelial dysfunction, hypercontractility, vasospasm, and a pro-thrombotic phenotype. AFD patients display increased intima-media thickness (IMT) and reduced flow-mediated dilation (FMD), indicating heightened cardiovascular risk. Nailfold capillaroscopy (NFC) shows promise in diagnosing and monitoring microcirculatory disorders in AFD, though it remains underexplored. Morphological evidence of AFD as a storage disorder can be demonstrated through electron microscopy and immunodetection of Gb3. Secondary pathophysiological disturbances at cellular, tissue, and organ levels contribute to the clinical manifestations, with prominent lysosomal inclusions observed in vascular, cardiac, renal, and neuronal cells. Chronic accumulation of Gb3 represents a state of ongoing toxicity, leading to increased cell turnover, particularly in vascular endothelial cells. AFD-related vascular pathology includes increased renin-angiotensin system activation, endothelial dysfunction, and smooth muscle cell proliferation, resulting in IMT increase. Furthermore, microvascular alterations, such as atypical capillaries observed through NFC, suggest early microvascular involvement. This review aims to unravel the complex interplay between inflammation, oxidative stress, and endothelial dysfunction in AFD, highlighting the potential connections between metabolic disturbances, oxidative stress, inflammation, and fibrosis in vascular and cardiac complications. By exploring novel cardiovascular risk factors and potential diagnostic tools, we can advance our understanding of these mechanisms, which extend beyond sphingolipid accumulation to include other significant contributors to disease pathogenesis. This comprehensive approach can pave the way for innovative therapeutic strategies and improved patient outcomes.

The role of podocyte injury in the pathogenesis of Fabry disease nephropathy.

Renal involvement is one of the most severe morbidities of Fabry disease (FD), a multisystemic lysosomal storage disease with an X-linked inheritance pattern. It results from pathogenic variants in the GLA gene (Xq22.2), which encodes the production of alpha-galactosidase A (α-Gal), responsible for glycosphingolipid metabolism. Insufficient activity of this lysosomal enzyme generates deposits of unprocessed intermediate substrates, especially globotriaosylceramide (Gb3) and derivatives, triggering cellular injury and subsequently, multiple organ dysfunction, including chronic nephropathy. Kidney injury in FD is classically attributed to Gb3 deposits in renal cells, with podocytes being the main target of the pathological process, in which structural and functional alterations are established early and severely. This configures a typical hereditary metabolic podocytopathy, whose clinical manifestations are proteinuria and progressive renal failure. Although late clinical outcomes and morphological changes are well established in this nephropathy, the molecular mechanisms that trigger and accelerate podocyte injury have not yet been fully elucidated. Podocytes are highly specialized and differentiated cells that cover the outer surface of glomerular capillaries, playing a crucial role in preserving the structure and function of the glomerular filtration barrier. They are frequent targets of injury in many nephropathies. Furthermore, dysfunction and depletion of glomerular podocytes are essential events implicated in the pathogenesis of chronic kidney disease progression. We will review the biology of podocytes and their crucial role in regulating the glomerular filtration barrier, analyzing the main pathogenic pathways involved in podocyte injury, especially related to FD nephropathy.

Fabry disease Enzyme Enhancement on migalastat Study: FEES.

BACKGROUND: There is limited information on the α-galactosidase A (α-Gal-A) in vivo response in Fabry patients receiving migalastat. In this single centre study, we evaluated changes from baseline in α-Gal A activity, lyso-Gb3 and other assessments in patients on migalastat. RESULTS: 79 patients were recruited (48 M:31F; median duration receiving migalastat 3.8 years [range = 0.4-14.9 years]). N215S was the commonest genotype in males (67 %) and females (29 %). Leukocyte α-Gal-A showed a positive change from baseline in males (n = 4; median = 20.05); females (n = 8; median = 26). Of these, 3 males and 1 female had N215S (median = 16.7), while 7 females and 1 male had other genotypes (median = 26). No significant changes observed in plasma α-Gal-A. Cross-sectional analysis of post-baseline data confirmed leukocyte α-Gal-A enhancement in males (n = 47; median = 20); females (n = 30; median = 72); N215S (n = 41; median = 29) and other genotypes (n = 36; median = 36.5). Plasma and dried blood spot (DBS) lyso-Gb3 correlated at baseline and post-baseline (r = 0.77 and r = 0.96; p=<0.0001). CONCLUSIONS: In the 12 patients with paired data, there was a median enzyme enhancement of 17.4 (relative change = 2.54) and 33 (relative change = 0.87) in males and in females, respectively. The cross-sectional post-baseline data in 47 patients corroborated leukocyte α-Gal-A enhancement on migalastat. Plasma and DBS lyso-Gb3 correlated well supporting DBS utility for disease monitoring.

Unveiling the untreated: development of a database algorithm to identify potential Fabry disease patients in Germany.

BACKGROUND: Fabry disease (FD), an X-linked lysosomal storage disorder, is caused by mutations in the gene encoding α-galactosidase A, resulting in lysosomal accumulation of globotriaosylceramide and other glycosphingolipids. Early detection of FD is challenging, accounting for delayed diagnosis and treatment initiation. This study aimed to develop an algorithm using a logistic regression model to facilitate early identification of patients based on ICD-10-GM coding using a German Sickness Fund Database. METHODS: The logistic regression model was fitted on a binary outcome variable based on either a treated FD cohort or a control cohort (without FD). Comorbidities specific to the involved organs were used as covariates to identify potential FD patients with ICD-10-GM E75.2 diagnosis but without any FD-specific medication. Specificity and sensitivity of the model were optimized to determine a likely threshold. The cut-point with the largest values for the Youden index and concordance probability method and the lowest value for closest to (0,1) was identified as 0.08 for each respective value. The sensitivity and specificity for this cut-point were 80.4% and 79.8%, respectively. Additionally, a sensitivity analysis of the potential FD patients with at least two codes of E75.2 diagnoses was performed. RESULTS: A total of 284 patients were identified in the potential FD cohort using the logistic regression model. Most potential FD patients were < 30 years old and female. The identification and incidence rates of FD in the potential FD cohort were markedly higher than those of the treated FD cohort. CONCLUSIONS: This model serves as a tool to identify potential FD patients using German insurance claims data.

Expanding the Neurological Phenotype of Anderson-Fabry Disease: Proof of Concept for an Extrapyramidal Neurodegenerative Pattern and Comparison with Monogenic Vascular Parkinsonism.

Anderson-Fabry disease (AFD) is a genetic sphingolipidosis involving virtually the entire body. Among its manifestation, the involvement of the central and peripheral nervous system is frequent. In recent decades, it has become evident that, besides cerebrovascular damage, a pure neuronal phenotype of AFD exists in the central nervous system, which is supported by clinical, pathological, and neuroimaging data. This neurodegenerative phenotype is often clinically characterized by an extrapyramidal component similar to the one seen in prodromal Parkinson's disease (PD). We analyzed the biological, clinical pathological, and neuroimaging data supporting this phenotype recently proposed in the literature. Moreover, we compared the neurodegenerative PD phenotype of AFD with a classical monogenic vascular disease responsible for vascular parkinsonism and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). A substantial difference in the clinical and neuroimaging features of neurodegenerative and vascular parkinsonism phenotypes emerged, with AFD being potentially responsible for both forms of the extrapyramidal involvement, and CADASIL mainly associated with the vascular subtype. The available studies share some limitations regarding both patients' information and neurological and genetic investigations. Further studies are needed to clarify the potential association between AFD and extrapyramidal manifestations.

The Missense Variant in the Signal Peptide of α-GLA Gene, c.13 A/G, Promotes Endoplasmic Reticular Stress and the Related Pathway's Activation.

Anderson-Fabry disease (AFD) is an X-linked multisystemic disorder with a heterogeneous phenotype, resulting from deficiency of the lysosomal enzyme α-galactosidase A (α-Gal A) and leading to globotriaosylceramide systemic accumulation. Lysosomal storage is not the unique player in organ failure and different mechanisms could drive tissue damage, including endoplasmic reticulum (ER) stress and its related signaling pathway's activation. We identified a new missense variant in the signal peptide of α-GLA gene, c.13 A/G, in a 55-year-old woman affected by chronic kidney disease, acroparesthesia, hypohidrosis, and deafness and exhibiting normal values of lysoGb3 and αGLA activity. The functional study of the new variant performed by its overexpression in HEK293T cells showed an increased protein expression of a key ER stress marker, GRP78, the pro-apoptotic BAX, the negative regulator of cell cycle p21, the pro-inflammatory cytokine, IL1ß, together with pNFkB, and the pro-fibrotic marker, N-cadherin. Transmission electron microscopy showed signs of ER injury and intra-lysosomal inclusions. The proband's PBMC exhibited higher expression of TGFß 1 and pNFkB compared to control. Our findings suggest that the new variant, although it did not affect enzymatic activity, could cause cellular damage by affecting ER homeostasis and promoting apoptosis, inflammation, and fibrosis. Further studies are needed to demonstrate the variant's contribution to cellular and tissue damage.

Plasma and platelet lipidome changes in Fabry disease.

BACKGROUND: Fabry disease (FD) is an X-linked lysosomal storage disorder characterized by the progressive accumulation of globotriaosylceramide (Gb3) leading to systemic manifestations such as chronic kidney disease, cardiomyopathy, and stroke. There is still a need for novel markers for improved FD screening and prognosis. Moreover, the pathological mechanisms in FD, which also include systemic inflammation and fibrosis, are not yet fully understood. METHODS: Plasma and platelets were obtained from 11 ERT (enzyme-replacement therapy)-treated symptomatic, 4 asymptomatic FD patients, and 13 healthy participants. A comprehensive targeted lipidomics analysis was conducted quantitating more than 550 lipid species. RESULTS: Sphingadiene (18:2;O2)-containing sphingolipid species, including Gb3 and galabiosylceramide (Ga2), were significantly increased in FD patients. Plasma levels of lyso-dihexosylceramides, sphingoid base 1-phosphates (S1P), and GM3 ganglioside were also altered in FD patients, as well as specific plasma ceramide ratios used in cardiovascular disease risk prediction. Gb3 did not increase in patients' platelets but displayed a high inter-individual variability in patients and healthy participants. Platelets accumulated, however, lyso-Gb3, acylcarnitines, C16:0-sphingolipids, and S1P. CONCLUSIONS: This study identified lipidome changes in plasma and platelets from FD patients, a possible involvement of platelets in FD, and potential new markers for screening and monitoring of this disease.

How Do Physical Activity and Exercise Affect Fabry Disease? Exploring a New Opportunity.

BACKGROUND: Fabry disease (FD) is a multisystem, monogenic, X-linked storage disorder caused by mutations in the GLA gene, resulting in reduced alfa-galactosidase A enzyme activity. This effect leads to the accumulation of glycosphingolipids, particularly globotriaosylceramide, in various tissues, including the heart, kidney, vasculature, smooth muscle, and peripheral nervous system. Hemizygous males are usually more severely affected than females, in whom random inactivation of an X chromosome may lead to variable phenotype. SUMMARY: Among the manifestations of FD, exercise intolerance is commonly diagnosed but often underestimated, even though it significantly limits quality of life, especially in young patients. This review primarily discusses the various pathophysiological mechanisms involved in exercise intolerance in FD patients, such as altered muscle composition, compromised cardiopulmonary framework, and peripheral neuropathy. Secondarily, it explores the potential effect of available therapy, including enzyme replacement therapy and chaperone therapy (migalastat), in reducing exercise intolerance while considering the potential impact of physical activity and exercise training as adjunctive treatments. CONCLUSION: Exercise intolerance has a major impact on the well-being of people with FD. Exercise training can play an important role in addition to drug therapy.

Inflammatory and Cardiovascular Biomarkers to Monitor Fabry Disease Progression.

Fabry disease is an invalidating multisystemic disorder affecting α-Galactosidase, a rate-limiting hydrolase dedicated to lipid catabolism. Non-metabolized substrates, such as Globotriaosylceramide and its derivatives trigger the direct or indirect activation of inflammatory events and endothelial dysfunction. In spite of the efficacy demonstrated by enzyme replacement therapy or pharmacological chaperones in delaying disease progression, few studies have analyzed whether these treatments can improve the pro-inflammatory state of FD patients. Therefore, the aim of this work was to assess cytokines and cardiovascular risk-related proteins detectable in plasma from FD patients, whether treated or not with ERT, to evaluate the reliability of these markers in monitoring disease stage and treatment effects. We identified inflammatory and endothelial dysfunction markers (ADAMTS-13, TNF-α, GDF-15, MIP-1ß, VEGFA, MPO, and MIC-1) that cooperate in a common pathway and are increased in FD patients' plasma samples. As shown by the assessment of these proteins over time, they can help to evaluate the risk of higher severity in FD, as well as ERT effects. Even though the analyzed proteins cannot be considered as proper biomarkers due to their non-specificity to FD, taken together they can provide a signature of reference molecules with prognostic value for early diagnosis, and evaluation of disease progression and treatment efficacy, using blood samples.

LysoGb3 quantification facilitates phenotypic categorization of Fabry disease patients: Insights gained by a novel MS/MS method.

BACKGROUND: Fabry disease (FD) is an X-linked lysosomal storage disease resulting from pathogenic variants in the GLA gene coding α-galactosidase A (AGAL) and cleaving terminal alpha-linked galactose. Globotriaosylceramide (Gb3) is the predominantly accumulated sphingolipid. Gb3, deacylated-Gb3 (lysoGb3), and methylated-Gb3 (metGb3) have been suggested as FD biomarkers. MATERIALS AND METHODS: We developed a novel LC-MS/MS method for assessing lysoGb3 levels in plasma and Gb3 and metGb3 in urine and tested 62 FD patients, 34 patients with GLA variants of unknown significance (VUS) and 59 healthy controls. AGAL activity in white blood cells (WBCs) and plasma was evaluated in parallel. RESULTS: In males, lysoGb3 concentrations in plasma separated classic and late-onset FD patients from each other and from individuals carrying GLA VUS and healthy controls. Calculating AGAL activity/plasmatic lysoGb3 ratio allowed to correctly categorize all females with classic and majority of patients with late-onset FD phenotypes. Correlation of AGAL activity in WBCS with lipid biomarkers identified threshold activity values under which the biomarkers' concentrations increase. CONCLUSION: We developed a novel simplified LC-MS/MS method for quantitation of plasma lysoGb3. AGAL activity/plasma lysoGb3 ratio was identified as the best predictor for FD. AGAL activity correlated with plasma lysoGb3 and corresponded to individual FD phenotypes.

CRISPR/Cas9-based GLA knockout to generate the female Fabry disease human induced pluripotent stem cell line MHHi001-A-15.

The X-linked lysosomal storage disorder Fabry disease originates from GLA gene mutations causing α-galactosidase A enzyme deficiency. Here we generated the GLA knockout hiPSC line MHHi001-A-15 (GLA-KOhiPSC) as an in vitro Fabry disease model by targeting exon 2 of the GLA gene by CRISPR/Cas9 in the established control hiPSC line MHHi001-A. GLA-KOhiPSCs retained the expression of pluripotency markers, trilineage differentiation potential, as well as normal karyotype and stem cell morphology but lacked α-galactosidase A enzyme activity. The GLA-KOhiPSCs represent a potent resource to not only study the Fabry disease manifestation but also screen for novel treatment options.

Effects of Enzyme Replacement Therapy on Cardiac MRI Findings in Fabry Disease: A Systematic Review and Meta-Analysis.

Purpose To perform a systematic review and meta-analysis to assess the effect of enzyme replacement therapy on cardiac MRI parameters in patients with Fabry disease. Materials and Methods A systematic literature search was conducted from January 1, 2000, through January 1, 2024, in PubMed, ClinicalTrials.gov, Embase, and Cochrane Library databases. Study outcomes were changes in the following parameters: (a) left ventricular wall mass (LVM), measured in grams; (b) LVM indexed to body mass index, measured in grams per meters squared; (c) maximum left ventricular wall thickness (MLVWT), measured in millimeters; (d) late gadolinium enhancement (LGE) extent, measured in percentage of LVM; and (e) native T1 mapping, measured in milliseconds. A random-effects meta-analysis of the pooled mean differences between baseline and follow-up parameters was conducted. The study protocol was registered in PROSPERO (CRD42022336223). Results The final analysis included 11 studies of a total of 445 patients with Fabry disease (mean age ± SD, 41 years ± 11; 277 male, 168 female). Between baseline and follow-up cardiac MRI, the following did not change: T1 mapping (mean difference, 6 msec [95% CI: -2, 15]; two studies, 70 patients, I2 = 88%) and LVM indexed (mean difference, -1 g/m2 [95% CI: -6, 3]; four studies, 290 patients, I2 = 81%). The following measures minimally decreased: LVM (mean difference, -18 g [95% CI: -33, -3]; seven studies, 107 patients, I2 = 96%) and MLVWT (mean difference, -1 mm [95% CI: -2, -0.02]; six studies, 151 patients, I2 = 90%). LGE extent increased (mean difference, 1% [95% CI: 1, 1]; three studies, 114 patients, I2 = 85%). Conclusion In patients with Fabry disease, enzyme replacement therapy was associated with stabilization of LVM, MLVWT, and T1 mapping values, whereas LGE extent mildly increased. Keywords: Fabry Disease, Enzyme Replacement Therapy (ERT), Cardiac MRI, Late Gadolinium Enhancement (LGE) Supplemental material is available for this article. © RSNA, 2024.

Ocular Manifestations of Fabry Disease: Report from a Tertiary Eye Care Center in Türkiye.

Objectives: To report ocular manifestations in patients with Fabry disease (FD) from a tertiary eye care center in Türkiye. Materials and Methods: This prospective, cross-sectional study included 30 eyes of 15 patients with FD. The diagnosis of FD was made based on a combination of clinical findings, genetic analysis, and biochemical evaluation. All participants underwent a detailed ophthalmic examination with special focus on the typical ocular features of FD (cornea verticillata, conjunctival aneurysms, cataract, retinal vessel tortuosity). Results: The mean age was 45±17 years (range: 22-75 years), with a female/male ratio of 2:3. All patients had tortuous conjunctival vessels and 12 patients (80%) had conjunctival aneurysms. Cornea verticillata was present in 10 patients (66.6%), lens opacification in 4 patients (26.6%), and retinal vascular tortuosity in 8 patients (53.3%). All patients had at least two different ocular findings; most (3 heterozygotes/7 hemizygotes) had a combination of corneal verticillata and conjunctival vessel abnormality. The conjunctiva, cornea, and retina were affected together in 5 hemizygous patients (33.3%). One hemizygous patient had all FDrelated ocular manifestations in both eyes. Conclusion: To our knowledge, this study is the first to describe the ocular manifestations of FD in the Turkish population. Although cornea verticillata is considered a hallmark of FD, it was absent in approximately one-third of patients. Moreover, cataract, another well-known feature of FD, was present in only 26.6% of the patients. Conjunctival vascular abnormality alone seems to be quite rare in FD, although it often accompanies other ocular manifestations. Therefore, recognition of other mild findings and special consideration of their associations may increase the diagnostic value of ocular findings in FD.

8th Update on Fabry Disease: Biomarkers, Progression and Treatment Opportunities in 2024.

Fabry Update.

Detection of α-Galactosidase A Reaction in Samples Extracted from Dried Blood Spots Using Ion-Sensitive Field Effect Transistors.

Fabry disease is a lysosomal storage disorder caused by a significant decrease in the activity or absence of the enzyme α-galactosidase A. The diagnostics of Fabry disease during newborn screening are reasonable, due to the availability of enzyme replacement therapy. This paper presents an electrochemical method using complementary metal-oxide semiconductor (CMOS)-compatible ion-sensitive field effect transistors (ISFETs) with hafnium oxide-sensitive surfaces for the detection of α-galactosidase A activity in dried blood spot extracts. The capability of ISFETs to detect the reaction catalyzed by α-galactosidase A was demonstrated. The buffer composition was optimized to provide suitable conditions for both enzyme and ISFET performance. The use of ISFET structures as sensor elements allowed for the label-free detection of enzymatic reactions with melibiose, a natural substrate of α-galactosidase A, instead of a synthetic fluorogenic one. ISFET chips were packaged with printed circuit boards and microfluidic reaction chambers to enable long-term signal measurement using a custom device. The packaged sensors were demonstrated to discriminate between normal and inhibited GLA activity in dried blood spots extracts. The described method offers a promising solution for increasing the widespread distribution of newborn screening of Fabry disease.