Fabry disease revisited: Management and treatment recommendations for adult patients

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.

[What is confirmed in the treatment of Fabry's disease?]

Fabry's disease is a rare X chromosome-linked inherited lysosomal storage disease characterized by insufficient metabolism of the substrate globotriaosylceramide (Gb3) due to reduced alpha-galactosidase A (AGAL) activity. Lysosomal Gb3 accumulation causes a multisystemic disease which, if untreated, reduces the life expectancy in females and males by around 10 and 20 years, respectively, due to progressive renal dysfunction, hypertrophic cardiomyopathy, cardiac arrhythmia and early occurrence of cerebral infarction. The diagnosis is confirmed by determining the reduced AGAL activity in leukocytes in males and molecular genetic detection of a -mutation causing the disease in females. The treatment comprises enzyme replacement therapy (ERT), agalsidase alfa, 0.2 mg/kg body weight (BW), agalsidase beta 1.0 mg/kg BW or pegunigalsidase alfa 1.0 mg/kg BW every 2 weeks i.v. or oral chaperone therapy (one capsule of migalastat 123 mg every other day) in the presence of amenable mutations. This article summarizes the data on the treatment of Fabry's disease and on complications in practice. The current guideline recommendations are addressed and new study results that could expand the therapeutic repertoire in the future are discussed.

Prevalence of Fabry disease in patients with chronic pain: Lessons from the DOUFAB and DOUFABIS studies

BACKGROUND

Fabry disease (FD) is a rare X-linked lysosomal disorder caused by alpha-galactosidase deficiency consecutive to a pathogenic variant in the GLA gene. Age at onset is highly variable, with a wide clinical spectrum including frequent renal, cardiac, skin and nervous system manifestations. Since pain can be an indicator of underlying FD, we wanted to estimate the prevalence of FD in a population of chronic pain patients.

METHODS

Two studies, DOUFAB and DOUFABIS, were carried out in expert centers for chronic pain to assess the prevalence of FD by measuring alpha galactosidase A activity in men and analysing the GLA gene in women.

RESULTS

Analysis of 893 patients, essentially adults, led to the diagnosis of FD in one female patient, now treated with enzyme replacement therapy.

CONCLUSIONS

The prevalence of FD is estimated about 1/1000 in our population of men and women suffering from various chronic pain. This is nearly the prevalence of FD observed in other previously screened high-risk populations with renal failure.

SIGNIFICANCE

Although a systematic search for FD does not seem relevant in the context of unexplained chronic pain in adults, a positive family history of FD or the presence of additional FD related organ features must lead to consider this rare disease diagnosis. Therefore, pain specialists need to be aware of main features of FD, including pain characteristics.

Prognostic Implications of Left Ventricular Hypertrophy and Mechanical Function in Fabry Disease: A Longitudinal Cohort Study

BACKGROUND

The prognostic value of different grades of left ventricular hypertrophy (LVH) and left ventricular (LV) mechanical function in Fabry disease is unclear. We aimed to evaluate the association between the severity of LVH, LV mechanical function, and clinical outcomes in Fabry disease.

METHODS

We conducted a retrospective cohort study from a single-center registry of adult patients with Fabry disease. Left ventricular mass index (LVMI) was measured by echocardiography. The severity of LVH was categorized by LVMI using the sex-specific cutoff values. Left ventricular mechanical function was measured as LV global longitudinal strain (GLS) by speckle-tracking analysis. The primary outcome was a composite of major adverse cardiovascular events (MACE) at 5 years, including heart failure hospitalization, sustained ventricular tachycardia, acute ischemic stroke, and all-cause mortality.

RESULTS

The study included 268 patients (age 50.4 ± 15.4 years, men 46.6%) with Fabry disease (83.2% IVS4+919G > A mutation), and 106 patients (39.6%) had LVH. Patients with mild, moderate, or severe LVH had 5-year MACE rates of 7.4%, 10%, and 30.5%, respectively (P < .001). Moreover, patients with impaired LV GLS (<14.1%) had a higher 5-year MACE rate than those with preserved LV GLS (32.1% vs 2.4%, P < .001). Severe LVH was an independent predictor of MACE compared with absence of LVH (adjusted hazard ratio, 12.73; 95% CI, 1.3-124.71; P = .03), after adjusting for age, sex, hypertension, hyperlipidemia, atrial fibrillation, renal function, average E/e', enzyme replacement therapy, and LV GLS. Patients with severe LVH and impaired LV GLS had the highest incidence for MACE (log-rank P < .05), irrespective of sex, genotypes, and whether receiving enzyme replacement therapy or not.

CONCLUSIONS

Sex-specific grading of LVH by LVMI is practical for risk stratification in patients with Fabry disease, and impaired LV GLS further refines the prognostication.

Reduction in kidney function decline and risk of severe clinical events in agalsidase beta-treated Fabry disease patients: a matched analysis from the Fabry Registry

Background

Patients with Fabry disease (FD, α-galactosidase A deficiency or absence) accumulate glycosphingolipids, leading to progressive dysfunction of kidneys, heart and nervous system. Generalizable real-world outcomes following agalsidase beta treatment initiation outside trials are limited. We investigated the associations of long-term agalsidase beta treatment with estimated glomerular filtration rate (eGFR) changes over time and the risk of developing a composite clinical event in a matched analysis of treated and untreated patients with FD.

Methods

Agalsidase beta-treated adult patients (aged ≥16 years) from the Fabry Registry and adult untreated patients from a natural history cohort were matched 1:1 and X:X (with one occurrence and multiple occurrences of each untreated patient, respectively) by sex, phenotype, age and (for eGFR slope analysis) baseline eGFR. Outcomes included eGFR slope over 5 years and composite clinical event risk (cardiovascular, cerebrovascular or renal event, or death) over 10+ years. As a surrogate indicator of therapeutic response in paediatric patients, the percentage experiencing normalization in plasma globotriaosylceramide (GL-3) from treatment initiation was assessed in patients aged 2 to <16 years.

Results

Overall, eGFR slopes for 1:1-matched untreated and treated adult patients [122 pairs (72.1% male)] were -3.19 and -1.47 mL/min/1.73 m2/year, respectively (reduction in rate of decline = 53.9%, P = .007), and for X:X-matched [122 untreated/950 treated (59.4% male)] were -3.29 and -1.56 mL/min/1.73 m2/year, respectively (reduction in rate of decline = 52.6%, P < .001). Agalsidase beta treatment was associated with lower risk of clinical events, with hazard ratios of 0.41 (P = .003) and 0.67 (P = .008) for 1:1-matched and X:X-matched analyses, respectively. Plasma GL-3 declined markedly in paediatric patients and normalized in most within 6 months of treatment initiation.

Conclusion

Agalsidase beta treatment preserves kidney function and delays progression to severe clinical events among adult patients with FD. Plasma GL-3 levels analysed in paediatric patients showed normalization of elevated pre-treatment levels in most patients.

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.

Renal and multisystem effectiveness of 3.9 years of migalastat in a global real-world cohort: Results from the followME Fabry Pathfinders registry

Fabry disease is a progressive, X-linked lysosomal disorder caused by reduced or absent α-galactosidase A activity due to GLA variants. The effects of migalastat were examined in a cohort of 125 Fabry patients with migalastat-amenable GLA variants in the followME Pathfinders registry (EUPAS20599), an ongoing, prospective, patient-focused registry evaluating outcomes for current Fabry disease treatments. We report annualised estimated glomerular filtration rate (eGFR) and Fabry-associated clinical events (FACEs) in a cohort of patients who had received ≥3 years of migalastat treatment in a real-world setting. As of August 2022, 125 patients (60% male) had a mean migalastat exposure of 3.9 years. At enrolment, median age was 58 years (males, 57; females, 60) with a mean eGFR of 83.7 mL/min/1.73 m2 (n = 122; males, 83.7; females, 83.8) and a median left ventricular mass index of 115.1 g/m2 (n = 61; males, 131.2; females, 98.0). Mean (95% confidence interval) eGFR annualised rate of change in the overall cohort (n = 116) was -0.9 (-10.8, 9.9) mL/min/1.73 m2/year with a similar rate of change observed across patients with varying levels of kidney function at enrolment. Despite population age and baseline morbidity, 80% of patients did not experience a FACE during the mean 3.9 years of migalastat exposure. The incidence of renal, cardiac, and cerebrovascular events was 2.0, 83.2, and 4.1 events per 1000 patient-years, respectively. These data support a role of migalastat in preserving renal function and multisystem effectiveness during ≥3 years of migalastat treatment in this real-world Fabry population.

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.

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.

Clinical outcomes in patients switching from agalsidase beta to migalastat: A Fabry Registry analysis

Fabry Registry data were analyzed among 83 agalsidase beta-treated patients with Fabry disease who switched to migalastat. Outcomes (estimated glomerular filtration rate [eGFR], urine protein-creatinine ratio [UPCR], plasma globotriaosylceramide [GL-3], plasma globotriaosylsphingosine [lyso-GL-3], interventricular septal wall thickness [IVST], left posterior wall thickness [LPWT], left ventricular mass index [LVMI]) were assessed using linear mixed models to estimate annual change over time in the pre- and postswitch periods. eGFR decreased throughout both periods (preswitch: -0.85 mL/min/1.73 m2/year; postswitch: -1.96 mL/min/1.73 m2/year; both p < 0.0001), with steeper decline postswitch (ppre/post = 0.01) in both classic and late-onset patients. UPCR increased significantly postswitch (ppre/post = 0.003) among classic patients and was stable in both periods among late-onset patients. GL-3 trajectories worsened postswitch across phenotypes (ppre/post = 0.0005 classic, 0.02 late-onset). LPWT was stable preswitch (0.07 mm/year, p = 0.25) and decreased postswitch (-0.51 mm/year, p = 0.0005; ppre/post = 0.0009), primarily among late-onset patients. IVST and LVMI slopes varied significantly by phenotype. Among classic patients, IVST and LVMI were stable and decreasing, respectively preswitch and increasing postswitch (ppre/post = 0.02 IVST, 0.01 LVMI). Among late-onset patients, IVST significantly decreased postswitch (ppre/post = 0.0003); LVMI was stable over time (ppre/post = 0.89). Ultimately, eGFR and GL-3 trajectories worsened postswitch across phenotypes, while UPCR and cardiac measures worsened among classic and stabilized/improved among late-onset patients. These findings indicate variability in long-term outcomes after switching from ERT to migalastat, underscoring the importance of careful monitoring.

Cracking the code of the cardiovascular enigma: hPSC-derived endothelial cells unveil the secrets of endothelial dysfunction

Endothelial dysfunction is a central contributor to the development of most cardiovascular diseases and is characterised by the reduced synthesis or bioavailability of the vasodilator nitric oxide together with other abnormalities such as inflammation, senescence, and oxidative stress. The use of patient-specific and genome-edited human pluripotent stem cell-derived endothelial cells (hPSC-ECs) has shed novel insights into the role of endothelial dysfunction in cardiovascular diseases with strong genetic components such as genetic cardiomyopathies and pulmonary arterial hypertension. However, their utility in studying complex multifactorial diseases such as atherosclerosis, metabolic syndrome and heart failure poses notable challenges. In this review, we provide an overview of the different methods used to generate and characterise hPSC-ECs before comprehensively assessing their effectiveness in cardiovascular disease modelling and high-throughput drug screening. Furthermore, we explore current obstacles that will need to be overcome to unleash the full potential of hPSC-ECs in facilitating patient-specific precision medicine. Addressing these challenges holds great promise in advancing our understanding of intricate cardiovascular diseases and in tailoring personalised therapeutic strategies.

Cases of Fabry Disease in Which Pathogenic Variants Are Not Detected in Parent-Child Pairs

A 15-year-old male has been experiencing fever, limb pain during exercise, and reduced sweating since childhood. During an investigation into his fever, a family history of Fabry disease was discovered, prompting a referral to our department. He was diagnosed with Fabry disease based on decreased alpha-galactosidase A (α-Gal A) activity. Concurrently, his mother was found to have experienced limb pain during fevers since childhood, and she was also diagnosed with Fabry disease based on decreased α-Gal A activity. In the genetic analysis of both individuals, the IVS1+17A>G GLA variant was identified. This variant is considered benign and not classified as a pathogenic variant. Enzyme replacement therapy has been effective in improving clinical symptoms. His sister, who has not been diagnosed with Fabry disease due to normal clinical symptoms and α-GAL A activity, also had the same variant. Among the various GLA variants, many are classified as benign rather than pathogenic. In the present cases, the possibility of other factors that cannot be identified by genetic analysis is suggested, making this case significant and worth reporting.

Genetic variants of unknown significance in alpha-galactosidase A: Cellular delineation from Fabry disease

Fabry disease (FD) is an X-linked multiorgan disorder caused by variants in the alpha-galactosidase A gene (GLA). Depending on the variant, disease phenotypes range from benign to life-threatening. More than 1000 GLA variants are known, but a link between genotype and phenotype in FD has not yet been established for all. p.A143T, p.D313Y, and p.S126G are frequent examples of variants of unknown significance (VUS). We have investigated the potential pathogenicity of these VUS combining clinical data with data obtained in human cellular in vitro systems. We have analyzed four different male subject-derived cell types for alpha-galactosidase A enzyme (GLA) activity and intracellular Gb3 load. Additionally, Gb3 load in skin tissue as well as clinical data were studied for correlates of disease manifestations. A reduction of GLA activity was observed in cells carrying p.A143T compared with controls (p < 0.05). In cells carrying the p.D313Y variant, a reduced GLA activity was found only in endothelial cells (p < 0.01) compared with controls. No pathological changes were observed in cells carrying the p.S126G variant. None of the VUS investigated caused intracellular Gb3 accumulation in any cell type. Our data of aberrant GLA activity in cells of p.A143T hemizygotes and overall normal cellular phenotypes in cells of p.D313Y and p.S126G hemizygotes contribute a basic science perspective to the clinically highly relevant discussion on VUS in GLA.

[Importance of lysosomal storage diseases in rheumatology]

Lysosomal storage diseases are a group of rare hereditary metabolic diseases. Due to a deficiency of lysosomal enzymes, complex substrates accumulate in the lysosomes of various organs. Depending on the affected enzyme, this results in clinically variable and chronic progressive multiorgan diseases. Diagnosis is often delayed. As clinical symptoms include the musculoskeletal system, an awareness of lysosomal storage diseases is of relevance to (pediatric) rheumatologists. This article is focused on Mucopolysaccharidosis type I‑S, Mucolipidosis type III, Gaucher disease and Fabry disease. When suspecting a lysosomal storage disease, enzyme activity should be determined in dried blood spots or leukocytes. For some diseases, specific biomarkers can additionally be analyzed. Diagnosis should be confirmed by genetic testing. As causal treatment options are available for three of the presented diseases, a timely diagnosis is very important.

Arrhythmogenesis in Fabry Disease

PURPOSE OF REVIEW

Fabry Disease (FD) is a rare lysosomal storage disorder characterised by multiorgan accumulation of glycosphingolipid due to deficiency in the enzyme α-galactosidase A. Cardiac sphingolipid accumulation triggers various types of arrhythmias, predominantly ventricular arrhythmia, bradyarrhythmia, and atrial fibrillation. Arrhythmia is likely the primary contributor to FD mortality with sudden cardiac death, the most frequent cardiac mode of death. Traditionally FD was seen as a storage cardiomyopathy triggering left ventricular hypertrophy, diastolic dysfunction, and ultimately, systolic dysfunction in advanced disease. The purpose of this review is to outline the current evidence exploring novel mechanisms underlying the arrhythmia substrate.

RECENT FINDINGS

There is growing evidence that FD cardiomyopathy is a primary arrhythmic disease with each stage of cardiomyopathy (accumulation, hypertrophy, inflammation, and fibrosis) contributing to the arrhythmia substrate via various intracellular, extracellular, and environmental mechanisms. It is therefore important to understand how these mechanisms contribute to an individual's risk of arrhythmia in FD. In this review, we outline the epidemiology of arrhythmia, pathophysiology of arrhythmogenesis, risk stratification, and cardiac therapy in FD. We explore how advances in conventional cardiac investigations performed in FD patients including 12-lead electrocardiography, transthoracic echocardiography, and cardiac magnetic resonance imaging have enabled early detection of pro-arrhythmic substrate. This has allowed for appropriate risk stratification of FD patients. This paves the way for future work exploring the development of therapeutic initiatives and risk prediction models to reduce the burden of arrhythmia.

Analysis of Globotriaosylceramide (Gb3) in Liquid Urine: A Straightforward Assay Using Tandem Mass Spectrometry

Fabry disease (FD) is a lysosomal storage disorder caused by variants in the GLA gene encoding α-galactosidase A, an enzyme required for catabolism of globotriaosylceramide (Gb3). Accumulation of Gb3 in patients' cells, tissues, and biological fluids causes clinical manifestations including ventricular hypertrophy, renal insufficiency, and strokes. This protocol describes a methodology to analyze urinary Gb3 and creatinine. Samples are diluted with an internal standard solution containing Gb3(C17:0) and creatinine-D3, centrifuged, and directly analyzed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) using an 8.7-min method. Eight Gb3 isoforms [C16:0, C18:0, C20:0, C22:1, C22:0, C24:1, C24:0, and (C24:0)OH] are analyzed and the total is normalized to creatinine. Confirmation ions are monitored to detect potential interferences. The Gb3 limit of quantification is 0.023 µg/ml. Its interday coefficients of variation (3 concentrations measured) are ≤15.4%. This method minimizes matrix effects (≤6.5%) and prevents adsorption or precipitation of Gb3. Urine samples are stable (bias <15%) for 2 days at 21°C, 7 days at 4°C, and 4 freeze/thaw cycles, whereas prepared samples are stable for 5 days at 21°C, and 14 days at 4°C. The Gb3/creatinine age-related upper reference limits (mean + 2 standard deviations) are 29 mg/mol creatinine (<7 years) and 14 mg/mol creatinine (≥7 years). This simple, robust protocol has been fully validated (ISO 15189) and provides a valuable tool for diagnosis and monitoring of FD patients. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Analysis of urinary globotriaosylceramide (Gb3) and creatinine by UHPLC-MS/MS Support Protocol 1: Preparation of the urinary quality controls Support Protocol 2: Preparation of the urine matrix used for the Gb3 calibration curve Support Protocol 3: Preparation of the Gb3 calibrators Support Protocol 4: Preparation of the working solution containing the internal standards Support Protocol 5: Preparation of the creatinine calibrators Support Protocol 6: Preparation of the UHPLC solutions and mobile phases.

Aseptic meningitis and Fabry disease

OBJECTIVE

Fabry disease is caused by enzymatic defects in alpha-galactosidase A that leads to the accumulation of glycosphingolipids throughout the body, resulting in a multisystemic disorder. The most common neurological manifestations are neuropathic pain, autonomic nervous system dysfunction and strokes, but some rarer neurological manifestations exist. Among these, aseptic meningitis is a possible complication. Our objectives were to measure the prevalence of this complication in a cohort of patients with Fabry disease, and to describe its clinical features.

METHODS

We conducted a retrospective review of Fabry disease patients followed at our tertiary referral center between 1995 and September 2023 with at least one episode of meningitis, and performed a systematic review to identify similar published cases.

RESULTS

Four patients out of 107 (3.7%) had at least one episode of aseptic meningitis. Our systematic review identified 25 other observations. The median age of these 29 patients was 29.0 years, the median cerebrospinal fluid leukocyte count was 24 cells/mm3 with a predominance of lymphocytes in 64.7% of cases. In 82.8% of the patients, the diagnosis of Fabry disease was unknown before the meningitis. Large artery stenosis was present in 17.2% of patients and 57.1% of patients had a recent stroke concomitant with the meningitis. Several differential diagnoses were evoked, such as multiple sclerosis or central nervous system vasculitis.

INTERPRETATION

Our study suggests that Fabry disease should be considered as a cause of aseptic meningitis. The pathophysiological mechanisms underlying meningeal inflammation remain largely unknown but may reflect the dysregulation of pro-inflammatory signaling pathways.

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.

No evidence of Fabry disease in a patient with the new p.Met70Val GLA gene variant

BACKGROUND

Fabry disease (FD) is a rare X-linked lysosomal storage disorder caused by variants in GLA gene leading to deficient α-galactosidase A enzyme activity. This deficiency leads to the accumulation of glycosphingolipids, particularly globotriaosylceramide (Gb3), in various tissues and organs, which can result in life-threatening complications. The clinical presentation of the disease can vary from the "classic" phenotype with pediatric onset and multi-organ involvement to the "later-onset" phenotype, which presents with predominantly cardiac symptoms. In recent years, advances in screening studies have led to the identification of an increasing number of variants of unknown significance that have not yet been described, and whose pathogenic role remains undetermined.

METHODS

In this clinical report, we describe the case of an asymptomatic adult female who was found to have a new variant of unknown significance, p.Met70Val. Given the unknown pathogenic role of this variant, a thorough analysis of the potential organ involvement was conducted. The clinical data were analyzed retrospectively.

RESULTS

The analysis revealed that there were no signs of significant organ involvement, and the benignity of the variant was confirmed.

CONCLUSION

This case underscores the importance of a comprehensive evaluation of new variants of unknown significance to establish their pathogenicity accurately.

Fabry-specific treatment in Australia: time to align eligibility criteria with international best practices

BACKGROUND

Disease-specific therapy aims to improve symptoms, stabilise current disease and delay progression in patients with Fabry disease. In Australia, treatment access is subject to eligibility criteria initially established in 2004. Patients and their clinicians question why these criteria have remained unchanged despite significant progress in disease understanding.

AIMS

Appraise the clinical quality of the Australian treatment access criteria.

METHODS

The Fabry Australia Medical Advisory Committee (N = 6) used the Appraisal of Guidelines for REsearch and Evaluation Global Rating Scale (AGREE II GRS) to assess the clinical quality of the current treatment eligibility criteria. They reviewed the literature, developed 17 clinical statements to help guide reforms of the eligibility criteria and achieved consensus (achievement of ≥75% agreement in the range 5-7 on a 7-point Likert scale) through anonymous voting. The findings were applied to develop proposals for revised classification and treatment initiation criteria.

RESULTS

The current treatment eligibility criteria underperformed on the AGREE II GRS. They are pragmatic but out-of-step with contemporary data. Consensus was achieved on all 17 proposed clinical statements. There was strong agreement to differentiate classical male Fabry patients to facilitate timelier access to Fabry-specific treatment. There was also agreement on the value of adopting relevant organ involvement criteria in classical female patients and patients with non-classical disease.

CONCLUSIONS

Australian access criteria are misaligned with current clinical evidence. The clinical statements and proposed classification and initiation criteria should prompt discussions to support more equitable access to treatment and better align Australian practice with contemporary evidence and international guidelines.

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-1β, 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.

Cold-evoked potentials in Fabry disease and polyneuropathy

Background

Fabry disease (FD) causes cold-evoked pain and impaired cold perception through small fiber damage, which also occurs in polyneuropathies (PNP) of other origins. The integrity of thinly myelinated fibers and the spinothalamic tract is assessable by cold-evoked potentials (CEPs). In this study, we aimed to assess the clinical value of CEP by investigating its associations with pain, autonomic measures, sensory loss, and neuropathic signs.

Methods

CEPs were examined at the hand and foot dorsum of patients with FD (n = 16) and PNP (n = 21) and healthy controls (n = 23). Sensory phenotyping was performed using quantitative sensory testing (QST). The painDETECT questionnaire (PDQ), FabryScan, and measures for the autonomic nervous system were applied. Group comparisons and correlation analyses were performed.

Results

CEPs of 87.5% of the FD and 85.7% of the PNP patients were eligible for statistical analysis. In all patients combined, CEP data correlated significantly with cold detection loss, PDQ items, pain, and autonomic measures. Abnormal CEP latency in FD patients was associated with an abnormal heart frequency variability item (r = -0.684; adjusted p = 0.04). In PNP patients, CEP latency correlated significantly with PDQ items, and CEP amplitude correlated with autonomic measures (r = 0.688, adjusted p = 0.008; r = 0.619, adjusted p = 0.024). Furthermore, mechanical pain thresholds differed significantly between FD (gain range) and PNP patients (loss range) (p = 0.01).

Conclusions

Abnormal CEPs were associated with current pain, neuropathic signs and symptoms, and an abnormal function of the autonomic nervous system. The latter has not been mirrored by QST parameters. Therefore, CEPs appear to deliver a wider spectrum of information on the sensory nervous system than QST alone.

The Effect of Fabry Disease Therapy on Bone Mineral Density

Fabry disease (FD) is an X-linked lysosomal storage disorder, characterised by the cellular accumulation of globotriaosylceramide due to impaired alpha-galactosidase A enzyme activity. FD may manifest with multisystem pathology, including reduced bone mineral density (BMD). Registry data suggest that the introduction of Fabry-specific therapies (enzyme replacement therapy or chaperone therapy) has led to significant improvements in overall patient outcomes; however, there are limited data on the impact on bone density. The aim of this study was to describe the effect of Fabry-specific therapies on longitudinal changes in bone mineral density (BMD) in FD. We performed a retrospective observational study analysing bone densitometry (DXA) in patients with genetically confirmed FD. Patients were grouped based on the use of Fabry-specific therapies. The between-group longitudinal change in BMD Z-score was analysed using linear mixed effects models. A total of 88 FD patients were analysed (50 untreated; 38 treated). The mean age at first DXA was 38.5 years in the untreated group (84% female) and 43.7 years in the treated group (34% female). There was no significant longitudinal between-group difference in the BMD Z-score at the lumbar spine. However, the Z-score per year at the total hip (β = -0.105, p < 0.001) and femoral neck (β = -0.081, p = 0.001) was significantly lower over time in the treated than the untreated group. This may reflect those receiving therapy having a more severe underlying disease. Nevertheless, this suggests that Fabry-specific therapies do not reverse all disease mechanisms and that the additional management of BMD may be required in this patient population.

Cardiopulmonary determinants of reduced exercise tolerance in Fabry disease

Fabry disease (FD), also known as Anderson-Fabry disease, is a hereditary disorder of glycosphingolipid metabolism, caused by a deficiency of the lysosomal alpha-galactosidase A enzyme. This causes a progressive accumulation of glycosphingolipids in tissues and organs which represents the main pathogenetic mechanism of FD. The disease is progressive and multisystemic and is characterized by early symptoms and late complications (renal, cardiac and neurological dysfunction). Fatigue and exercise intolerance are early common symptoms in FD patients but the specific causes are still to be defined. In this narrative review, we deal with the contribution of cardiac and pulmonary dysfunctions in determining fatigue and exercise intolerance in FD patients.

Multivalent pyrrolidines acting as pharmacological chaperones against Gaucher disease

A concise asymmetric synthesis of clickable enantiomeric pyrrolidines was achieved using Crabbé-Ma allenation. The synthesized iminosugars were grafted by copper-free strain-promoted alkyne-azide cycloaddition onto phosphorus dendrimers. The hexavalent and dodecavalent pyrrolidines were evaluated as β-glucocerebrosidase inhibitors. The level of inhibition suggests that monofluorocyclooctatriazole group may contribute to the affinity for the protein leading to potent multivalent inhibitors. Docking studies were carried out to rationalize these results. Then, the iminosugars clusters were evaluated as pharmacological chaperones in Gaucher patients' fibroblasts. An increase in β-glucocerebrosidase activity was observed with hexavalent and dodecavalent pyrrolidines at concentrations as low as 1 µM and 0.1 µM, respectively. These iminosugar clusters constitute the first example of multivalent pyrrolidines acting as pharmacological chaperones against Gaucher disease.

The Diagnostic and Therapeutic Implications of Phenocopies and Mimics of Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a common myocardial disease defined by increased left ventricular wall thickness unexplained by loading conditions. HCM frequently is caused by pathogenic variants in sarcomeric protein genes, but several other syndromic, metabolic, infiltrative, and neuromuscular diseases can result in HCM phenocopies. This review summarizes the current understanding of these HCM mimics, highlighting their importance across the life course. The central role of a comprehensive, multiparametric diagnostic approach and the potential of precision medicine in tailoring treatment strategies are emphasized.

Potential Usefulness of Lifetime Globotriaosylsphingosine Exposure at Diagnosis and Baseline Modified Disease Severity Score in Early-Diagnosed Patients With Fabry Disease

BACKGROUND

Fabry disease (FD) is a lysosomal storage disease caused by a deficit of α-galactosidase A (GAL). Recently, plasma globotriaosylsphingosine (lyso-Gb3), a pathogenic analog of a substrate of GAL, has been suggested as a potential biomarker for FD, and disease severity scores, such as the Mainz Severity Score Index (MSSI), the Disease Severity Scoring System (DS3), and FASTEX (FAbry STabilization indEX), are useful tools for evaluating the severity of signs and symptoms in symptomatic FD patients. However, a more useful method of evaluating disease severity in early-diagnosed FD patients such as children, adult females, and asymptomatic patients is needed. Here, we proposed modified MSSI and DS3 scores to which we added phenotype, urinary mulberry bodies, and history of past pain attacks and examined the clinical usefulness of lyso-Gb3 and modified scores for early-diagnosed FD patients.

RESULT

In 13 early-diagnosed FD patients, we developed modified MSSI and DS3 scores and examined the correlation of lifetime lyso-Gb3 exposure at diagnosis with the conventional or modified scores. Lifetime lyso-Gb3 exposure was positively correlated only with the modified DS3 score. Additionally, we examined the long-term changes in plasma lyso-Gb3 concentration and in conventional MSSI, DS3, and FASTEX. In males, plasma lyso-Gb3 concentration decreased more rapidly than in females. In all patients, the severity scores were mild and remained nearly stable throughout the follow-up period.

CONCLUSION

Our data suggest that lifetime lyso-Gb3 exposure and the modified DS3 score are useful in early-diagnosed patients.

A case series of Fabry diseases with CKD in Japan

BACKGROUND

It is well known that kidney injury is vital organ damage in Fabry disease (FD). Renin-angiotensin system (RAS) inhibitors are known to reduce proteinuria in patients with chronic kidney disease (CKD) by dilating the glomerular export arteries and reducing intraglomerular pressure. This improvement in intraglomerular pressure, although lowering the glomerular filtration rate, is thought to prevent renal damage and be renoprotective in the long term. RAS inhibitors may be effective in FD patients with proteinuria to prevent the progression of kidney disease, however, the degree to which they are used in clinical practice is unknown.

METHODS

The J-CKD-DB-Ex is a comprehensive multicenter database that automatically extracts medical data on CKD patients. J-CKD-DB-Ex contains data on 187,398 patients in five medical centers. FD patients were identified by ICD-10. Clinical data and prescriptions of FD patients between January 1 of 2014, and December 31 of 2020 were used for the analysis.

RESULTS

We identified 39 patients with FD from the J-CKD-DB-Ex including those with suspected FD. We confirmed 22 patients as FD. Half of the patients received RAS inhibitors. RAS inhibitors tended to be used in CKD patients with more severe renal impairment.

CONCLUSIONS

This case series revealed the actual clinical practice of FD patients with CKD. In particular, we found cases in which patients had proteinuria, but were not treated with RAS inhibitors. The database was shown to be useful in assessing the clinical patterns of patients with rare diseases.

mRNA therapies: Pioneering a new era in rare genetic disease treatment

Rare genetic diseases, often referred to as orphan diseases due to their low prevalence and limited treatment options, have long posed significant challenges to our medical system. In recent years, Messenger RNA (mRNA) therapy has emerged as a highly promising treatment approach for various diseases caused by genetic mutations. Chemically modified mRNA is introduced into cells using carriers like lipid-based nanoparticles (LNPs), producing functional proteins that compensate for genetic deficiencies. Given the advantages of precise dosing, biocompatibility, transient expression, and minimal risk of genomic integration, mRNA therapies can safely and effectively correct genetic defects in rare diseases and improve symptoms. Currently, dozens of mRNA drugs targeting rare diseases are undergoing clinical trials. This comprehensive review summarizes the progress of mRNA therapy in treating rare genetic diseases. It introduces the development, molecular design, and delivery systems of mRNA therapy, highlighting their research progress in rare genetic diseases based on protein replacement and gene editing. The review also summarizes research progress in various rare disease models and clinical trials. Additionally, it discusses the challenges and future prospects of mRNA therapy. Researchers are encouraged to join this field and collaborate to advance the clinical translation of mRNA therapy, bringing hope to patients with rare genetic diseases.

A systematic literature review on the health-related quality of life and economic burden of Fabry disease

BACKGROUND

Fabry disease (FD) is a rare lysosomal storage disease associated with glycolipid accumulation that impacts multiple physiological systems. We conducted a systematic literature review (SLR) to characterize the humanistic (quality of life [QoL]) and economic burden of FD.

METHODS

Searches were conducted in the Embase, MEDLINE®, and MEDLINE® In-Process databases from inception to January 19, 2022. Conference abstracts of specified congresses were manually searched. Additional searches were performed in the Cochrane and ProQuest databases for the humanistic SLR and the National Health Service Economic Evaluations Database for the economic SLR. Studies of patients with FD of any sex, race, and age, and published in the English language were included. There was no restriction on intervention or comparator. For the humanistic SLR, studies that reported utility data, database/registry-based studies, questionnaires/surveys, and cohort studies were included. For the economic SLR, studies reporting economic evaluations or assessing the cost of illness and resource use were included.

RESULTS

Of the 1363 records identified in the humanistic search, 36 studies were included. The most commonly used QoL assessments were the 36-item Short-Form Health Survey (n = 16), EQ-5D questionnaire descriptive system or visual analog scale (n = 9), and the Brief Pain Inventory (n = 8). Reduced QoL was reported in patients with FD compared with healthy populations across multiple domains, including pain, physical functioning, and depressive symptoms. Multiple variables-including sex, age, disease severity, and treatment status-impacted QoL. Of the 711 records identified in the economic burden search, 18 studies were included. FD was associated with high cost and healthcare resource use. Contributors to the cost burden included enzyme replacement therapy, healthcare, and social care. In the seven studies that reported health utility values, lower utility scores were generally associated with more complications (including cardiac, renal, and cerebrovascular morbidities) and with classical disease in males.

CONCLUSION

FD remains associated with a high cost and healthcare resource use burden, and reduced QoL compared with healthy populations. Integrating information from QoL and economic assessments may help to identify interventions that are likely to be of most value to patients with FD.

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.

Long-Term Clinical-Pathologic Results of Enzyme Replacement Therapy in Prehypertrophic Fabry Disease Cardiomyopathy

BACKGROUND

The limited ability of enzyme replacement therapy (ERT) in removing globotriaosylceramide from cardiomyocytes is recognized for advanced Fabry disease cardiomyopathy (FDCM). Prehypertrophic FDCM is believed to be cured or stabilized by ERT. However, no pathologic confirmation is available. We report here on the long-term clinical-pathologic impact of ERT on prehypertrophic FDCM.

METHODS AND RESULTS

Fifteen patients with Fabry disease with left ventricular maximal wall thickness ≤10.5 mm at cardiac magnetic resonance required endomyocardial biopsy because of angina and ventricular arrhythmias. Endomyocardial biopsy showed coronary small-vessel disease in the angina cohort, and vacuoles in smooth muscle cells and cardiomyocytes ≈20% of the cell surface containing myelin bodies at electron microscopy. Patients received α-agalsidase in 8 cases, and β-agalsidase in 7 cases. Both groups experienced symptom improvement except 1 patients treated with α-agalsidase and 1 treated with β-agalsidase. After ERT administration ranging from 4 to 20 years, all patients had control cardiac magnetic resonance and left ventricular endomyocardial biopsy because of persistence of symptoms or patient inquiry on disease resolution. In 13 asymptomatic patients with FDCM, left ventricular maximal wall thickness and left ventricular mass, cardiomyocyte diameter, vacuole surface/cell surface ratio, and vessels remained unchanged or minimally increased (left ventricular mass increased by <2%) even after 20 years of observation, and storage material was still present at electron microscopy. In 2 symptomatic patients, FDCM progressed, with larger and more engulfed by globotriaosylceramide myocytes being associated with myocardial virus-negative lymphocytic inflammation.

CONCLUSIONS

ERT stabilizes storage deposits and myocyte dimensions in 87% of patients with prehypertrophic FDCM. Globotriaosylceramide is never completely removed even after long-term treatment. Immune-mediated myocardial inflammation can overlap, limiting ERT activity.

Newborn genetic screening for Fabry disease: Insights from a retrospective analysis in Nanjing, China

Fabry disease (FD), an X-linked disorder resulting from dysfunction of α-galactosidase A, can result in significant complications. Early intervention yields better outcomes, but misdiagnosis or delayed diagnosis is common, impacting prognosis. Thus, early detection is crucial in the clinical diagnosis and treatment of FD. While newborn screening for FD has been implemented in certain regions, challenges persist in enzyme activity detection techniques, particularly for female and late-onset patients. Further exploration of improved screening strategies is warranted. This study retrospectively analyzed genetic screening results for pathogenic GLA variants in 17,171 newborns. The results indicated an estimated incidence of FD in the Nanjing region of China of approximately 1 in 1321. The most prevalent pathogenic variant among potential FD patients was c.640-801G > A (46.15 %). Furthermore, the residual enzyme activity of the pathogenic variant c.911G > C was marginally higher than that of other variants, and suggesting that genetic screening may be more effective in identifying potential female and late-onset patients compared to enzyme activity testing. This research offers initial insights into the effectiveness of GLA genetic screening and serves as a reference for early diagnosis, treatment, and genetic counseling in FD.

Fabry disease: a rare disorder calling for personalized medicine

Fabry Disease (FD) is a genetic disease caused by a deficiency in the activity of lysosomal galactosidase A (α-GalA), an enzyme responsible for the catabolism of globotriaosylceramide (Gb3). Since lysosomes are present throughout the body and play a crucial role in catabolism and recycling of cytosolic compounds, FD can affect multiple organs and result in various symptoms, including renal, cardiovascular, neurological, cutaneous, and ophthalmic manifestations. Due to the nonspecific symptoms and the rarity of FD, it is often diagnosed late in life. However, introducing targeted therapies such as enzyme replacement therapy (ERT) and chaperone therapy has significantly improved FD's natural history and prognosis by restoring α-GalA enzyme activity. Despite the advancements, there are limitations to the currently available therapies, which has prompted research into new potential treatments for FD, including alternative forms of enzyme replacement therapy, substrate reduction therapy, mRNA therapy, and genetic therapy. In this review, we analyze the epidemiology, pathophysiology, and treatment of FD, with particular emphasis on promising therapeutic opportunities that could shift the treatment of this rare disease from a standardized to a personalized approach soon.

Pegunigalsidase alfa: a novel, pegylated recombinant alpha-galactosidase enzyme for the treatment of Fabry disease

Fabry disease, a rare X-linked genetic disorder, results from pathogenic variants in GLA, leading to deficient lysosomal α-galactosidase A enzyme activity and multi-organ manifestations. Since 2001, enzyme replacement therapy (ERT), using agalsidase alfa or agalsidase beta, has been the mainstay treatment, albeit with limitations such as rapid clearance and immunogenicity. Pegunigalsidase alfa, a novel PEGylated recombinant alpha-galactosidase, offers promise as an alternative. Produced in plant cells, pegunigalsidase alfa exhibits enhanced stability, prolonged half-life, and reduced immunogenicity due to pegylation. A phase 1/2 clinical trial demonstrated Gb3 clearance from renal capillary endothelial cells and its 48-month extension study revealed notable outcomes in renal function preservation. Three phase 3 clinical trials (BRIDGE, BRIGHT, and BALANCE) have shown favorable efficacy and safety profile, although caution is warranted in interpreting the results of BRIDGE and BRIGHT which lacked control groups. In BALANCE, the pivotal phase 3 trial comparing pegunigalsidase alfa with agalsidase beta, an intention-to-treat analysis of the eGFR decline over 2 years showed that the intergroup difference [95%confidence interval] in the median slope was -0.36 mL/min/1.73 m2/year [-2.44; 1.73]. The confidence interval had a lower limit above the prespecified value of -3 mL/min/1.73 m2/year and included zero. Despite challenges such as occasional hypersensitivity reactions and immune-complex-mediated glomerulonephritis, pegunigalsidase alfa approval by the European Medicines Agency and the Food and Drug Administration represents a significant addition to Fabry disease therapeutic landscape providing an option for patients in whom enzyme replacement therapy with current formulations is poorly tolerated or poorly effective.

Patient-reported experience with Fabry disease and its management in the real-world setting: results from a double-blind, cross-sectional survey of 280 respondents

BACKGROUND

Fabry disease (FD) is a rare X-linked lysosomal storage disorder with a heterogeneous clinical presentation. Patients with FD may exhibit early signs/symptoms including neuropathic pain, gastrointestinal complaints, and dermatologic manifestations. FD may ultimately progress to renal, neurologic, and cardiac dysfunction. Current treatments for FD have significantly improved the management and outcomes for patients with FD, but important clinical and convenience limitations still exist.

METHODS

To illuminate the impact of FD on daily life from the patient's perspective, we asked adult patients (≥ 18 years old) with FD in the United States and Canada to complete a 33-question online survey to assess patient-reported disease severity, management, and treatment outcomes.

RESULTS

A total of 280 respondents with FD completed the survey; they had a mean age of 47 years, and 68% (191/280) were women. Most were currently receiving FD treatment (84%, 234/280) with enzyme replacement therapy (ERT) (89%, 208/234) or chaperone therapy (11%, 26/234). Common symptoms included low energy/fatigue (72%, 201/280), tingling (62%, 174/280) or pain in the hands/feet (60%, 168/280), ringing in ears/hearing loss (54%, 151/280), general body pains/pain crises (51%, 143/280), and abdominal/stomach pain (50%, 140/280). More than half (51%, 144/280) of respondents reported their symptoms as bothersome (38%, 106/280) or difficult to control (14%, 38/280). Temporary symptom worsening between infusions was reported by about half of respondents: 51% (108/211) currently receiving ERT and 48% (14/29) previously receiving ERT. Only 48% (59/122) of respondents reported their symptom worsening to their physician. Of those who reported it, 41% (24/59) said that their physician prescribed medication to manage their symptoms or changed their treatment regimen.

CONCLUSIONS

Our analysis highlights the gap between current standard-of-care in disease monitoring and patient perception of disease progression among patients with FD. This information may be helpful for healthcare providers and drug developers seeking to improve the care of patients with FD by addressing unmet needs of high relevance.

A Systematic Review on Safety and Efficacy of Migalastat for the treatment of Fabry's Disease

INTRODUCTION

Fabry's disease (FD) is a genetic lysosomal storage disorder characterized by α-galactosidase A (α-Gal A) lost/reduced activity. We aim to systematically assess the safety and efficacy of Migalastat, an oral pharmacological chaperone, that has been approved for the treatment of FD in patients with amenable mutations.

METHODS

We conducted literature search following the PRISMA guidelines in major databases up to 4 February 2024, for studies that assessed the clinical outcomes of migalastat in patients with FD. The New Castle Ottawa Scale was used to evaluate the quality of the included studies.

RESULTS

A total of 2141 records were identified through database searches and register searches, amongst which 26 records were screened, and 12 of these were excluded. The remaining 14 reports were sought for retrieval. The 12 retrieved articles were assessed for eligibility and their quality was assessed after their inclusion. Amongst the included studies, 5 were of high quality, 6 were of medium quality, and 1 was of low quality.

CONCLUSION

Migalastat showed varied effects on enzyme activity and substrate levels, with gender-specific differences noted in GL-3 substrate activity and eGFR. Overall, it improved cardiac and renal outcomes similarly to enzyme replacement therapy, with a comparable safety profile.

Outcomes and management of kidney transplant recipients with Fabry disease: a review

Fabry disease is an X-linked inheritable lysosomal storage disease caused by various mutations of the galactosidase α gene resulting in α-galactosidase deficiency. Chronic kidney disease (CKD) is one of the most significant consequences of Fabry disease, with risk of end-stage kidney disease (ESKD) in this population. Like for other patients with ESKD, kidney transplant is the optimal treatment for Fabry disease patients with ESKD. However, enzyme replacement therapy and newer Fabry disease treatments remain important to mitigate other end organ damage such as cardiomyopathy post transplantation. This review is a primer on Fabry disease, which examines the outcomes of disease in the context of kidney transplant prior to, and during, the enzyme replacement treatment era, medical treatment of kidney transplant recipients with Fabry disease, and progress in screening studies.

Genetic Diagnosis of Adult Hemodialysis Patients With Unknown Etiology

Introduction

Kidney disease of unknown etiology accounts for 1 in 10 adult end-stage renal disease (ESRD) cases worldwide. The aim of this study is to clarify the genetic background of patients with chronic kidney disease (CKD) of unknown etiology who initiated renal replacement therapy (RRT) in adulthood.

Methods

This is a multicenter cross-sectional cohort study. Of the 1164 patients who attended 4 dialysis clinics in Japan, we first selected patients who started RRT between the ages of 20 and 49 years. After excluding patients with apparent causes of CKD (e.g., diabetic nephropathy, polycystic kidney disease (PKD) with family history, patients who underwent renal biopsy), 90 patients with CKD of unknown cause were included. The 298 genes associated with CKD were analyzed using capture-based targeted next-generation sequencing.

Results

Of the 90 patients, 10 (11.1%) had pathogenic variants in CKD-causing genes and 17 (18.9%) had variant of unknown significance (VUS). Three patients had PKD1 pathogenic variants, and 1 patient had PKD1 and COL4A4 pathogenic variants. In addition, 2 patients were diagnosed with atypical hemolytic uremic syndrome (aHUS) due to C3 or CFHR5. One patient each was diagnosed with Alport syndrome due to COL4A4 and COL4A3 variants, nephronophthisis due to NPHP1 variants, Fabry disease due to GLA variants, and autosomal-dominant tubulointerstitial kidney disease due to UMOD variants. Genetic diagnoses were not concordant with clinical diagnoses, except for patients with PKD1 variant.

Conclusion

This largest study on genetic analysis in hemodialysis-dependent adults revealed the presence of undiagnosed inherited kidney diseases.

What should rheumatologists know about Gaucher disease and Fabry disease? Connecting the dots for an overview

Gaucher and Fabry diseases are lysosomal storage disorders in which deficient enzyme activity leads to pathological accumulation of sphingolipids. These diseases have a broad phenotypic presentation. Musculoskeletal symptoms and pain complaints are frequently reported by patients. Thus, rheumatologists can be contacted by these patients, contributing to the correct diagnosis, earlier indication of appropriate treatment and improvement of their prognosis. This review describes important concepts about Gaucher and Fabry diseases that rheumatologists should understand to improve patients' quality of life and change the natural history of these diseases.

Lysosomal storage disorders identified in adult population from India: Experience of a tertiary genetic centre and review of literature

Lysosomal storage disorders (LSDs) in adults have milder phenotype and variable age at presentation. Several studies have described the phenotype, genotype and treatment outcomes for adult-onset LSDs like Gaucher, Fabry, Pompe disease and others. We describe the first systematic study on the occurrence of LSDs in an adult population from India. It describes, the key clinical signs seen in these patients and those from literature review that can aid in early detection. Of 2102 biochemically diagnosed LSDs cases, 32 adult patients were identified with LSDs. Based on the clinical suspicion, screening test and enzyme study was carried out. Twenty-two patients were subjected to a genetic study to identify the causative variant in a respective gene. Of the 32 adult patients, we observed a maximum percentage of 37.5% (n = 12) cases with Gaucher disease, followed by 13% (n = 4) with Fabry disease. We found 10% of cases with MPS IVA and MPS I, and 9% cases with Pompe. Single case of adult mucolipidosis III and two cases each of Type 1 Sialidosis, Niemann-Pick disease B and metachromatic leukodystrophy were identified. We observed two common variants p.Leu483Pro and p.Ala487Thr in the GBA1 gene in 23% of Indian patients with adult Gaucher disease. No common variants were observed in other aforementioned LSDs. Study identified 50% of Fabry patients and 4% of Gaucher patients diagnosed at our centre to be adults. The prevalence of adult Pompe patients was low (3.4%) as compared to 80% reported in the Caucasian population. Adult LSDs such as, MPS III, GM1/GM2 gangliosidosis and Krabbe disease were not identified in our cohort.

Use of T1 mapping in cardiac MRI for the follow-up of Fabry disease in a pediatric population

Background

Fabry disease (FD) is a rare X-linked lysosomal disorder caused by pathogenic variants in the alpha-galactosidase-A gene (GLA). Life threatening complications in adulthood include chronic kidney failure, strokes and the cardiac involvement which is the leading cause of mortality. Usually, it presents with hypertrophic cardiomyopathy, together with arrhythmia and conduction abnormalities. An early indicator is decreased T1 value on cardiac magnetic resonance (CMR). Enzyme replacement therapy (ERT) is effective on some extra-cardiac symptoms but its effect on cardiac lesions depends on the level of initial myocardial lesions. CMR is routinely used to monitor cardiac involvement in FD due to its capacity for tissular characterization. However, there is a lack of data on the pediatric population to understand how to integrate CMR into early therapeutic decisions.

Method

Monocentric longitudinal study carried out at Montpellier University Hospital from 2016 to 2022. All pediatric patients with FD were evaluated over time with clinical, biological, and cardiac imaging (CMR, echocardiography).

Results

Out of the six patients included, (3 males), five were treated with ERT during the study. Low T1 values were observed in 4 patients. The normalization of T1 values was observed after 4 years of ERT in 3 patients.

Conclusion

Due to the lack of strong clinical and biological markers of FD in pediatric patients, initiation and follow-up of ERT efficacy remain challenging. CMR with T1-mapping, a noninvasive method, could play a role in the evaluation of early cardiac impairment in young patients at diagnosis and during follow-up with or without ERT.

Infertility in Fabry's Disease: role of hypoxia and inflammation in determining testicular damage

Introduction

Fabry's disease (FD) is a genetic X-linked systemic and progressive rare disease characterized by the accumulation of globotriaosylceramide (GB3) into the lysosomes of many tissues. FD is due to loss-of-function mutations of α-galactosidase, a key-enzyme for lysosomal catabolism of glycosphingolipids, which accumulate as glycolipid bodies (GB). In homozygous males the progressive deposition of GB3 into the cells leads to clinical symptoms in CNS, skin, kidney, etc. In testis GB accumulation causes infertility and alterations of spermatogenesis. However, the precise damaging mechanism is still unknown. Our hypothesis is that GB accumulation reduces blood vessel lumen and increases the distance of vessels from both stromal cells and seminiferous parenchyma; this, in turn, impairs oxygen and nutrients diffusion leading to subcellular degradation of seminiferous epithelium and sterility.

Methods

To test this hypothesis, we have studied a 42-year-old patient presenting a severe FD and infertility, with reduced number of spermatozoa, but preserved sexual activity. Testicular biopsies were analyzed by optical (OM) and transmission electron microscopy (TEM). Activation and cellular localization of HIF-1α and NFκB was analyzed by immunofluorescence (IF) and RT-PCR on homogeneous tissue fractions after laser capture microdissection (LCMD).

Results

OM and TEM showed that GB were abundant in vessel wall cells and in interstitial cells. By contrast, GB were absent in seminiferous epithelium, Sertoli's and Leydig's cells. However, seminiferous tubular epithelium and Sertoli's cells showed reduced diameter, thickening of basement membrane and tunica propria, and swollen or degenerated spermatogonia. IF showed an accumulation of HIF-1α in stromal cells but not in seminiferous tubules. On the contrary, NFκB fluorescence was evident in tubules, but very low in interstitial cells. Finally, RT-PCR analysis on LCMD fractions showed the expression of pro-inflammatory genes connected to the HIF-1α/NFκB inflammatory-like pathway.

Conclusion

Our study demonstrates that infertility in FD may be caused by reduced oxygen and nutrients due to GB accumulation in blood vessels cells. Reduced oxygen and nutrients alter HIF-1α/NFκB expression and localization while activating HIF-1α/NFκB driven-inflammation-like response damaging seminiferous tubular epithelium and Sertoli's cells.

Baseline Characteristics of Fabry Disease "Amenable" Migalastat Patients in Argentinian Cohort

Fabry disease (FD) is a multisystem lysosomal storage disorder induced by genetic variants in the alpha-galactosidase A (αGalA) gene. Some FD patients have GLA variants with a reduction in overall αGalA enzymatic activity due to mutated proteins with reduced stability, caused by protein misfolding and premature degradation, but the αGalA catalytic activity remains conserved ("amenable" genetic variants). To correct this misfolding and to prevent premature degradation, migalastat, a small iminosugar molecule was developed. We report the clinical characteristics of FD "amenable" cohort patients from Argentina, prior to starting treatment with migalastat. Seventeen Fabry adult patients were recruited from 13 Argentinian Centers; 8 males (47.1%) and 9 females (52.9%) were included. All genotypes included were missense-type "amenables" mutations. Some classic FD typical early manifestations were more frequent in patients with "classic" versus "late-onset" FD phenotype (pain, p=0.002; cornea verticillata, p=0.019). There was a statistically significant difference in estimated glomerular filtration rate in the "classic" versus "late-onset" phenotype (p=0.026) but no difference between genders (p=0.695). Left ventricular mass was similar between genders (p=0.145) and phenotypes (p=0.303). Cardiovascular risk factors were present among "late-onset" females (obesity 50% and smoke 25%). In patients who started "de novo" migalastat, the main indications were (i) heart disease, (ii) kidney damage, and (iii) pain, while in "switched from prior enzyme replacement therapy" patients, the most frequent indication was "patient decision;" this coincides with publications by other authors.

Experience with cascade screening: A comprehensive family pedigree analysis of two index patients with Fabry disease

The wide range of clinical symptoms observed in patients with Fabry disease (FD) often leads to delays in diagnosis and initiation of treatment. Delayed initiation of therapy may result in end-organ damage, such as chronic renal failure, hypertrophic cardiomyopathy, and stroke. Although some tools are available to identify undiagnosed patients, new comprehensive screening methods are needed. In this study, the outcomes of the cascade screening applied to three index cases with FD from 2 familes were investigated. In the pedigree analysis, 280 individuals were included; out of them, 131 individuals underwent genetic testing and cascade screening for FD. During the screening program, a total of 45 individuals were diagnosed, with a diagnostic ratio of 1:15. The average age at diagnosis for all individuals was 30.9 ± 17.7 years, and %25 were pediatric cases (mean age 9.5 ± 5.9 years). Thirty affected relatives were diagnosed from the two index cases in Family 1 and 15 individuals were diagnosed from one index case in Family 2. There were 13 consanguineous marriages observed among 2 pedigres, in two both spouses  were affected, leading to two homozygous affected daughters in one couple. In regions where there is a high prevalence of consanguineous marriages, implementing the cascade screening approach to identify all individuals at risk can be beneficial for patients with FD, specifically women and children.

Prevalence of Fabry disease and GLA variants in young patients with acute stroke: The challenge to widen the screening. The Fabry-Stroke Italian Registry

BACKGROUND

Fabry disease (FD) is a treatable X-linked lysosomal storage disorder caused by GLA gene variants leading to alpha-galactosidase A deficiency. FD is a rare cause of stroke, and it is still controversial whether in stroke patients FD should be searched from the beginning or at the end of the diagnostic workup (in cryptogenic strokes).

METHODS

Fabry-Stroke Italian Registry is a prospective, multicentric screening involving 33 stroke units. FD was sought by measuring α-galactosidase A activity (males) and by genetic tests (males with reduced enzyme activity and females) in patients aged 18-60 years hospitalized for TIA, ischemic stroke, or intracerebral hemorrhage. We diagnosed FD in patients with 1) already known pathogenic GLA variants; 2) novel GLA variants if additional clinical, laboratory, or family-derived criteria were present.

RESULTS

Out of 1906 patients, we found a GLA variant in 15 (0.79%; 95%CI 0.44-1.29) with a certain FD diagnosis in 3 (0.16%; 95%CI 0.03-0.46) patients, none of whom had hemorrhage. We identified 1 novel pathogenic GLA variant. Ischemic stroke etiologies in carriers of GLA variants were: cardioaortic embolism (33%), small artery occlusion (27%), other causes (20%), and undetermined (20%). Mild severity, recurrence, previous TIA, acroparesthesias, hearing loss, and small artery occlusion were predictors of GLA variant.

CONCLUSION

In this large multicenter cohort the frequency of FD and GLA variants was consistent with previous reports. Limiting the screening for GLA variants to patients with cryptogenic stroke may miss up to 80% of diagnoses. Some easily recognizable clinical features could help select patients for FD screening.

Hemoporfin-mediated photodynamic therapy for angiokeratoma corporis diffusum: A case report

SIGNIFICANCE

Angiokeratoma corporis diffusum (ACD) is one type of angiokeratomas which are characterized on histology by superficial dilated capillaries with epidermal proliferation. ACD seriously influences patients' appearance and quality of life. Many therapies have been used to solved this problem. However, all the treatments have not been proved very effective. Hemoporfin-mediated photodynamic therapy (Hemoporfin-PDT) was considered recently as a promising treatment for PWS according to the principle of targeted photodynamic destruction of the vascular wall of the lesion.

APPROACH

APPROACH: A 27-year-old male patient diagnosed with angiokeratoma corporis diffusum (ACD) by skin tissue biopsy has undergone pulsed dye laser for times, but the result was unsatisfying. After evaluating and obtaining the patient's agreement, we utilized Hemoporfin-PDT with 530 nm LED green light to treat ACD. When followed up in the 1 year after 2 treatments, the patient was pleased with the efficacy that most red papules on his face disappeared.

RESULTS

The patient achieved great improvement after two treatments.

CONCLUSIONS

Hemoporfin-PDT could be used to treat ACD.

Fatigue as hallmark of Fabry disease: role of bioenergetic alterations

Fabry disease (FD) is a lysosomal storage disorder due to the impaired activity of the α-galactosidase A (GLA) enzyme which induces Gb3 deposition and multiorgan dysfunction. Exercise intolerance and fatigue are frequent and early findings in FD patients, representing a self-standing clinical phenotype with a significant impact on the patient's quality of life. Several determinants can trigger fatigability in Fabry patients, including psychological factors, cardiopulmonary dysfunctions, and primary alterations of skeletal muscle. The "metabolic hypothesis" to explain skeletal muscle symptoms and fatigability in Fabry patients is growing acknowledged. In this report, we will focus on the primary alterations of the motor system emphasizing the role of skeletal muscle metabolic disarrangement in determining the altered exercise tolerance in Fabry patients. We will discuss the most recent findings about the metabolic profile associated with Fabry disease offering new insights for diagnosis, management, and therapy.

Anderson-Fabry Disease: Red Flags for Early Diagnosis of Cardiac Involvement

Anderson-Fabry disease (AFD) is a lysosome storage disorder resulting from an X-linked inheritance of a mutation in the galactosidase A (GLA) gene encoding for the enzyme alpha-galactosidase A (α-GAL A). This mutation results in a deficiency or absence of α-GAL A activity, with a progressive intracellular deposition of glycosphingolipids leading to organ dysfunction and failure. Cardiac damage starts early in life, often occurring sub-clinically before overt cardiac symptoms. Left ventricular hypertrophy represents a common cardiac manifestation, albeit conduction system impairment, arrhythmias, and valvular abnormalities may also characterize AFD. Even in consideration of pleiotropic manifestation, diagnosis is often challenging. Thus, knowledge of cardiac and extracardiac diagnostic "red flags" is needed to guide a timely diagnosis. Indeed, considering its systemic involvement, a multidisciplinary approach may be helpful in discerning AFD-related cardiac disease. Beyond clinical pearls, a practical approach to assist clinicians in diagnosing AFD includes optimal management of biochemical tests, genetic tests, and cardiac biopsy. We extensively reviewed the current literature on AFD cardiomyopathy, focusing on cardiac "red flags" that may represent key diagnostic tools to establish a timely diagnosis. Furthermore, clinical findings to identify patients at higher risk of sudden death are also highlighted.