Fabry disease: baseline medical characteristics of a cohort of 1765 males and females in the Fabry Registry

Globotriaosylsphingosine improves risk stratification of kidney progression in Fabry disease patients

BACKGROUND

Kidney damage is common in patients with Fabry disease (FD), but more accurate information about the risk of progression to kidney failure is needed for clinical decision-making. In particular, FD patients with mild renal involvement often lack timely intervention and treatment. We aimed to utilize a model to predict the risk of renal progression in FD patients.

METHODS

Between November 2011 and November 2019, ERT-naive patients with FD were recruited from three medical centers in China. To assess the risk of a 50% decline in the estimated glomerular filtration rate (eGFR) or end-stage kidney disease (ESKD), Cox proportional hazards models were utilized. The performance of these models was assessed using discrimination, calibration, and reclassification.

RESULTS

A total of 117 individuals were enrolled. The mean follow-up time was 4.8 years, during which 35 patients (29.9 %) progressed to the composite renal outcomes. Male sex, baseline proteinuria, eGFR and globotriaosylsphingosine (Lyso-Gb3) were found to be independent risk factors for kidney progression by the Cox model, based on which a combined model containing those clinical variables and Lyso-Gb3 and clinical models including only clinical indicators were constructed. The two prediction models had relatively good performance, with similar model fit measured by R2 (59.8 % vs. 61.1 %) and AIC (51.54 vs. 50.08) and a slight increase in the C statistic (0.949 vs. 0.951). Calibration curves indicated closer alignment between predicted and actual renal outcomes in the combined model. Furthermore, subgroup analysis revealed that Lyso-Gb3 significantly improved the predictive performance of the combined model for kidney prognosis in low-risk patients with a baseline eGFR over 60 ml/min/1.73 m2 or proteinuria levels less than 1 g/d when compared to the clinical model.

CONCLUSIONS

Lyso-Gb3 improves the prediction of kidney outcomes in FD patients with a low risk of progression, suggesting that these patients may benefit from early intervention to assist in clinical management. These findings need to be externally validated.

In vitro characterization of cells derived from a patient with the GLA variant c.376A>G (p.S126G) highlights a non-pathogenic role in Fabry disease

Fabry disease (FD) is a life-limiting disorder characterized by intracellular globotriaosylceramide (Gb3) accumulations. The underlying α-galactosidase A (α-GAL A) deficiency is caused by variants in the gene GLA. Variants of unknown significance (VUS) are frequently found in GLA and challenge clinical management. Here, we investigated a 49-year old man with cryptogenic lacunar cerebral stroke and the chance finding of the VUS S126G, who was sent to our center for diagnosis and initiation of a costly and life-long FD-specific treatment. We combined clinical examination with in vitro investigations of dermal fibroblasts (HDF), induced pluripotent stem cells (iPSC), and iPSC-derived sensory neurons. We analyzed α-GAL A activity in iPSC, Gb3 accumulation in all three cell types, and action potential firing in sensory neurons. Neurological examination and small nerve fiber assessment was normal except for reduced distal skin innervation. S126G iPSC showed normal α-GAL A activity compared to controls and no Gb3 deposits were found in all three cell types. Baseline electrophysiological characteristics of S126G neurons showed no difference compared to healthy controls as investigated by patch-clamp recordings. We pioneer multi-level cellular characterization of the VUS S126G using three cell types derived from a patient and provide further evidence for the benign nature of S126G in GLA, which is of great importance in the management of such cases in clinical practice.

Cochleovestibular Signs As the First Manifestation of Fabry Disease: A Case Report and Literature Review

Fabry disease (FD) is an X-linked lysosomal storage disorder characterized by alpha-galactosidase A deficiency, resulting in globotriaosylceramide accumulation and diverse clinical manifestations. We report a case of a 22-year-old male presenting with cochleovestibular disorders as the initial FD manifestation, alongside a literature review. Diagnostic evaluation revealed reduced alpha-galactosidase A activity, confirming FD. Cochleovestibular involvement, although underexplored, significantly affects FD patients, often presenting with sudden deafness or sensorineural hearing loss. Prompt diagnosis and enzyme replacement therapy are crucial for managing FD. Otolaryngologists play a key role in early detection and intervention. This case underscores the importance of considering FD in cases of hearing loss, tinnitus, or vertigo, emphasizing the need for heightened awareness among healthcare providers.

Cluster analysis and visualisation of electronic health records data to identify undiagnosed patients with rare genetic diseases

Rare genetic diseases affect 5-8% of the population but are often undiagnosed or misdiagnosed. Electronic health records (EHR) contain large amounts of data, which provide opportunities for analysing and mining. Data mining, in the form of cluster analysis and visualisation, was performed on a database containing deidentified health records of 1.28 million patients across 3 major hospitals in Singapore, in a bid to improve the diagnostic process for patients who are living with an undiagnosed rare disease, specifically focusing on Fabry Disease and Familial Hypercholesterolaemia (FH). On a baseline of 4 patients, we identified 2 additional patients with potential diagnosis of Fabry disease, suggesting a potential 50% increase in diagnosis. Similarly, we identified > 12,000 individuals who fulfil the clinical and laboratory criteria for FH but had not been diagnosed previously. This proof-of-concept study showed that it is possible to perform mining on EHR data albeit with some challenges and limitations.

Case report: enzyme replacement therapy for Fabry disease presenting with proteinuria and ventricular septal thickening

Fabry disease (FD) is an uncommon, X-linked, lysosomal storage disease that causes defects in the glycosphingolipid metabolic pathway due to deficient or absent lysosomal α-galactosidase (α-Gal A) activity. This leads to the accumulation of globotriaosylceramide (GL-3) within lysosomes in a wide range of cells, including endothelial, cardiac, renal, and corneal cells, and consequently, the progressive appearance of clinical symptoms in target organs. Enzyme replacement therapy (ERT), which involves the exogenous supplementation of α-Gal A enzyme and has been successfully administered for treating FD.Here, we report a case of a 37-year-old male with complaints of recurrent proteinuria and ventricular septal thickening. A renal biopsy revealed vacuolization and foamy changes in podocytes, and the presence of myelin-like bodies and zebra bodies. The white blood cell α-Gal A activity was very low, while the Lyso-GL-3 level was high. Additionally, genetic analysis revealed a gene variant c.902G > A p. Arg301Gln. The patient was diagnosed with FD, and subsequently received intravenous ERT with a dose of Agalsidase α (0.2 mg/kg, 17.5 mg every 2 weeks). Currently, the values of proteinuria and ventricular septum thickness remain stable during the 6-month follow-up. Initiating ERT at an early age can effectively decrease the deposition of GL-3, attenuate the progressive clinical manifestations of FD, and provide greater long-term benefits.

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.

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.

Fabry App: the value of a portable technology in recording day-to-day patient monitored information in patients with Fabry disease

BACKGROUND

Fabry disease is a rare inherited disorder resulting from deficient α-galactosidase A enzyme activity. Common disease manifestations are sweating abnormalities, neuropathic pain, gastrointestinal symptoms and fatigue. Challenges are faced by health care professionals in evaluating symptom burden in the current clinical setting, and the demand for alternative methods for monitoring disease-specific symptoms has seen an acceleration in recent years. Smartphone technologies offer the potential for continuity of care and surveillance. As a part of a quality improvement project, a disease specific app was developed in collaboration with a software company (Health Touch Ltd) and made available for patient use in May 2018. The Fabry mobile app records five categories: pain, gastrointestinal symptoms, sweating, activity levels, medications. Fabry disease patients with gastrointestinal and pain symptoms attending the Lysosomal Storage Disorders Unit of the Royal Free London NHS Foundation Trust were reviewed to assess eligibility and invited to download the app for recording their symptoms (activity, sweating, pain and gastrointestinal) and medications. Patient-generated data were transmitted to a secure website for clinicians to review.

RESULTS

One-hundred and thirty-nine symptomatic Fabry disease patients who had a smartphone (iPhone or android) were invited to download the app. Sixty-seven patients (26 males and 41 females; median age, 49 years [range, 20-81]) downloaded and tracked the Fabry App at least once. The median frequency of use per patient was 6 (range, 1-629). Pain in the hands and abdominal pain were significantly higher (p = 0.009 and p = 0.007, respectively) in patients with classic phenotype compared with patients with non-classic phenotypes.

CONCLUSIONS

We demonstrated the feasibility and acceptability of a smartphone app to facilitate the remote assessment and monitoring of Fabry disease symptom burden on a daily/weekly basis, as an alternative to the current standard of care that requires patients to recall their symptoms during 6 to 12 monthly annual clinic visits. Patients who were more likely to use the app had greater disease burden. This innovation has the potential to assess disease progression, early therapeutic intervention, thereby decreasing the burden of morbidity and mortality among Fabry patients, and to record long-term effects of Fabry-specific therapies.

Impact of kidney biopsy on deciding when to initiate enzyme replacement therapy in children with Fabry disease

BACKGROUND

Recommendations on when to start enzyme replacement therapy (ERT) in children with Fabry disease (FD) differ between guidelines. In this study, kidney biopsies of a cohort of 14 untreated children and one treated child were analyzed for their morphologic changes to determine whether early initiation of ERT is indicated.

METHODS

All pediatric FD patients (< 18 years old) diagnosed between 2003 and 2021 in our department who received a kidney biopsy were enrolled. Clinical symptoms; laboratory parameters regarding kidney function, such as eGFR, plasma urea, protein-creatinine, and albumin/creatinine ratio; and 14 kidney biopsies prior to ERT and one under treatment were retrospectively analyzed.

RESULTS

A total of 14 patients were enrolled, including 9 male and 5 female children, aged 3-18 years (median age 11). Seven of the enrolled children were 10 years old or younger. Histological analysis of kidney biopsy samples revealed severe vacuolization and accumulation of inclusions in podocytes and renal tubules. The majority of cases had no FD-specific clinical or laboratory features independent of age, gender, or genotype. The youngest FD patient presenting with isolated abnormal kidney biopsy was 3 years old.

CONCLUSIONS

We demonstrate that histological lesions, typical for FD, can be observed in kidney biopsies at a very young age in patients without classical clinical symptoms or laboratory abnormalities. Thus, we recommend kidney biopsies as a possible tool for early diagnosis of renal involvement in FD. As a consequence of these early biopsy findings without a clinical correlate, an early initiation of ERT should be considered. A higher resolution version of the Graphical abstract is available as Supplementary information.

Hydroxychloroquine-Induced Renal Phospholipidosis: Case Report and Review of Differential Diagnoses

Introduction

Renal phospholipidosis describes the accumulation of phospholipids in the lysosomes of kidney cells, in particular podocytes. Originally, this was described primarily in the context of the lysosomal storage disorder Fabry disease. It is now known that a variety of drugs can lead to the accumulation of lysosomal phospholipids.

Case Presentation

We present the case of a 69-year-old female patient suffering chronic kidney disease and systemic lupus erythematosus who underwent a kidney biopsy because of a further increase in serum creatinine levels. There was no evidence of lupus nephritis, but electron microscopy showed zebra bodies as a morphological sign of phospholipidosis. This was most likely drug-induced after 25 years of continuous medication with hydroxychloroquine. A renal biopsy 2 years and 6 months earlier, when the renal function of the patient was distinctively better, showed no signs of renal phospholipidosis. Afterward, medication with hydroxychloroquine was discontinued, and renal function parameters remained stable in the 1-year course.

Conclusion

This case raises the question of how severely impaired renal function affects the risk of hydroxychloroquine-induced renal phospholipidosis and underlines that hydroxychloroquine should be administered with caution in patients with kidney insufficiency. Moreover, we provide a review of the causes of renal phospholipidosis, which have been described in the literature and give an overview of possible differential diagnoses in cases with histologically proven phospholipidosis in renal biopsies.

The Importance of Early Treatment of Inherited Neuromuscular Conditions

There has been tremendous progress in treatment of neuromuscular diseases over the last 20 years, which has transformed the natural history of these severely debilitating conditions. Although the factors that determine the response to therapy are many and in some instance remain to be fully elucidated, early treatment clearly has a major impact on patient outcomes across a number of inherited neuromuscular conditions. To improve patient care and outcomes, clinicians should be aware of neuromuscular conditions that require prompt treatment initiation. This review describes data that underscore the importance of early treatment of children with inherited neuromuscular conditions with an emphasis on data resulting from newborn screening efforts.

Fabry Disease in Women: Genetic Basis, Available Biomarkers, and Clinical Manifestations

Fabry Disease (FD) is a rare lysosomal storage disorder caused by mutations in the GLA gene on the X chromosome, leading to a deficiency in α-galactosidase A (AGAL) enzyme activity. This leads to the accumulation of glycosphingolipids, primarily globotriaosylceramide (Gb3), in vital organs such as the kidneys, heart, and nervous system. While FD was initially considered predominantly affecting males, recent studies have uncovered that heterozygous Fabry women, carrying a single mutated GLA gene, can manifest a wide array of clinical symptoms, challenging the notion of asymptomatic carriers. The mechanisms underlying the diverse clinical manifestations in females remain not fully understood due to X-chromosome inactivation (XCI). XCI also known as "lyonization", involves the random inactivation of one of the two X chromosomes. This process is considered a potential factor influencing phenotypic variation. This review delves into the complex landscape of FD in women, discussing its genetic basis, the available biomarkers, clinical manifestations, and the potential impact of XCI on disease severity. Additionally, it highlights the challenges faced by heterozygous Fabry women, both in terms of their disease burden and interactions with healthcare professionals. Current treatment options, including enzyme replacement therapy, are discussed, along with the need for healthcare providers to be well-informed about FD in women, ultimately contributing to improved patient care and quality of life.

Multidisciplinary and multidimensional approaches to transplantation in children with rare genetic kidney diseases

In this review, we describe the multidisciplinary, multidimensional care required to optimize outcomes for pediatric transplant recipients with rare genetic kidney diseases. Transplant success, recipient survival, and improvement in quality of life depend on collaboration between patients, families, and a team of specialists with medical, as well as nonmedical expertise. A multidisciplinary transplant team composed of experts from medicine, surgery, nursing, nutrition, social services, transplant coordination, psychology, and pharmacology, is now standard in most transplant centers and is critical to the success of a transplant. In addition to these professionals, other specialists, such as cardiologists, urologists, geneticists, metabolic disease specialists, occupational therapists, case management, child life, chaplain, and palliative care services, have a crucial role to play in the preparation, surgery, and follow-up care, especially when a pediatric patient has a rare genetic disorder leading to renal involvement, and the need for transplantation. In order to describe this multidisciplinary care, we divide the genetic renal diseases into five subgroups-metabolic and tubular disorders, glomerular diseases, congenital anomalies of the kidney and urinary tract, ciliopathies including cystic diseases, and miscellaneous renal conditions; and describe for each, the need for care beyond that provided by the standard transplant team members.

Systems analyses of the Fabry kidney transcriptome and its response to enzyme replacement therapy identified and cross-validated enzyme replacement therapy-resistant targets amenable to drug repurposing

Fabry disease is a rare disorder caused by variations in the alpha-galactosidase gene. To a degree, Fabry disease is manageable via enzyme replacement therapy (ERT). By understanding the molecular basis of Fabry nephropathy (FN) and ERT's long-term impact, here we aimed to provide a framework for selection of potential disease biomarkers and drug targets. We obtained biopsies from eight control individuals and two independent FN cohorts comprising 16 individuals taken prior to and after up to ten years of ERT, and performed RNAseq analysis. Combining pathway-centered analyses with network-science allowed computation of transcriptional landscapes from four nephron compartments and their integration with existing proteome and drug-target interactome data. Comparing these transcriptional landscapes revealed high inter-cohort heterogeneity. Kidney compartment transcriptional landscapes comprehensively reflected differences in FN cohort characteristics. With exception of a few aspects, in particular arteries, early ERT in patients with classical Fabry could lastingly revert FN gene expression patterns to closely match that of control individuals. Pathways nonetheless consistently altered in both FN cohorts pre-ERT were mostly in glomeruli and arteries and related to the same biological themes. While keratinization-related processes in glomeruli were sensitive to ERT, a majority of alterations, such as transporter activity and responses to stimuli, remained dysregulated or reemerged despite ERT. Inferring an ERT-resistant genetic module of expressed genes identified 69 drugs for potential repurposing matching the proteins encoded by 12 genes. Thus, we identified and cross-validated ERT-resistant gene product modules that, when leveraged with external data, allowed estimating their suitability as biomarkers to potentially track disease course or treatment efficacy and potential targets for adjunct pharmaceutical treatment.

A questionnaire survey on the diagnosis and treatment of Fabry nephropathy in clinical practice

BACKGROUND

Fabry nephropathy is characterized by a deficiency of lysosomal alpha-galactosidase A, which results in proteinuria and kidney disease. The ineffectiveness of enzyme replacement therapy (ERT) for severe kidney failure highlights the need for early detection and meaningful markers. However, because the diagnosis and treatment of Fabry disease can vary according to the expertise of physicians, we evaluated the opinions of Korean specialists.

METHODS

A questionnaire regarding the management of Fabry nephropathy was emailed to healthcare providers with the experience or ability to treat individuals with Fabry nephropathy.

RESULTS

Of the 70 experts who responded to the survey, 43 were nephrologists, and 64.3% of the respondents reported having treated patients with Fabry disease. Pediatricians are treating primarily patients with classic types of the disease, while nephrologists and cardiologists are treating more patients with variant types. Only 40.7% of non-nephrologists agreed that a kidney biopsy was required at the time of diagnosis, compared with 81.4% of nephrologists. Thirty-eight of 70 respondents (54.3%) reported measuring globotriaosylsphingosine (lyso-Gb3) as a biomarker. The most common period to measure lyso-Gb3 was at the time of diagnosis, followed by after ERT, before ERT, and at screening. For the stage at which ERT should begin, microalbuminuria and proteinuria were chosen by 51.8% and 28.6% of respondents, respectively.

CONCLUSION

Nephrologists are more likely to treat variant Fabry disease rather than classic cases, and they agree that ERT should be initiated early in Fabry nephropathy, using lyso-Gb3 as a biomarker.

Management of pain in Fabry disease in the UK clinical setting: consensus findings from an expert Delphi panel

BACKGROUND

Fabry disease is a rare, X-linked inherited lysosomal storage disorder, that manifests as a heterogeneous disease with renal, cardiac and nervous system involvement. The most common pain experienced by people with Fabry disease are episodes of neuropathic pain reported in up to 80% of classical hemizygous male patients and up to 65% of heterozygous female patients. No clear consensus exists within UK clinical practice for the assessment and management of pain in Fabry disease based on agreed clinical practice and clinical experience. Here we describe a modified Delphi initiative to establish expert consensus on management of pain in Fabry disease in the UK clinical setting.

METHODS

Delphi panel members were identified based on their demonstrated expertise in managing adult or paediatric patients with Fabry disease in the UK and recruited by an independent third-party administrator. Ten expert panellists agreed to participate in two survey rounds, during which they remained anonymous to each other. Circulation of the questionnaires, and collection and processing of the panel's responses were conducted between September 2021 and December 2021. All questions required an answer.

RESULTS

The Delphi panel reached a consensus on 21 out of 41 aspects of pain assessment and management of pain in Fabry disease. These encompassed steps in the care pathway from the goals of therapy through to holistic support, including the use of gabapentin and carbamazepine as first-line analgesic medications for the treatment of neuropathic pain in Fabry disease, as well as the proactive management of symptoms of anxiety and/or depression associated with Fabry pain.

CONCLUSIONS

The consensus panel outcomes reported here have highlighted strengths in current UK clinical practice, along with unmet needs for further research and agreement. This consensus is intended to prompt the next steps towards developing clinical guidelines.

Global reach of over 20 years of experience in the patient-centered Fabry Registry: Advancement of Fabry disease expertise and dissemination of real-world evidence to the Fabry community

Fabry disease (FD, α-galactosidase A deficiency) is a rare, progressive, complex lysosomal storage disorder affecting multiple organ systems with a diverse spectrum of clinical phenotypes, particularly among female patients. Knowledge of its clinical course was still limited in 2001 when FD-specific therapies first became available and the Fabry Registry (NCT00196742; sponsor: Sanofi) was initiated as a global observational study. The Fabry Registry has now been operational for over 20 years, overseen by expert Boards of Advisors, and has collected real-world demographic and longitudinal clinical data from more than 8000 individuals with FD. Leveraging the accumulating evidence base, multidisciplinary collaborations have resulted in the creation of 32 peer-reviewed scientific publications, which have contributed to the greatly expanded knowledge on the onset and progression of FD, its clinical management, the role of sex and genetics, the outcomes of enzyme replacement therapy with agalsidase beta, and prognostic factors. We review how the Fabry Registry has evolved from its inception to become the largest global source of real-world FD patient data, and how the generated scientific evidence has helped to better inform the medical community, individuals living with FD, patient organizations, and other stakeholders. The patient-centered Fabry Registry fosters collaborative research partnerships with the overarching goal of optimizing the clinical management of patients with FD and is well positioned to add to its past achievements.

Sex Differences in Heart Failure: What Do We Know?

Heart failure (HF) remains an important global health issue, substantially contributing to morbidity and mortality. According to epidemiological studies, men and women face nearly equivalent lifetime risks for HF. However, their experiences diverge significantly when it comes to HF subtypes: men tend to develop HF with reduced ejection fraction more frequently, whereas women are predominantly affected by HF with preserved ejection fraction. This divergence underlines the presence of numerous sex-based disparities across various facets of HF, encompassing aspects such as risk factors, clinical presentation, underlying pathophysiology, and response to therapy. Despite these apparent discrepancies, our understanding of them is far from complete, with key knowledge gaps still existing. Current guidelines from various professional societies acknowledge the existence of sex-based differences in HF management, yet they are lacking in providing explicit, actionable recommendations tailored to these differences. In this comprehensive review, we delve deeper into these sex-specific differences within the context of HF, critically examining associated definitions, risk factors, and therapeutic strategies. We provide a specific emphasis on aspects exclusive to women, such as the impact of pregnancy-induced hypertension and premature menopause, as these unique factors warrant greater attention in the broader HF discussion. Additionally, we aim to clarify ongoing controversies and knowledge gaps pertaining to the pharmacological treatment of HF and the sex-specific indications for cardiac implantable electronic devices. By shining a light on these issues, we hope to stimulate a more nuanced understanding and promote the development of more sex-responsive approaches in HF management.

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

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

The patients` perspective on home-based infusion: A longitudinal observational study in the German healthcare setting for patients with lysosomal storage disorders treated with enzyme replacement therapy

Background

Lysosomal storage diseases (LSDs), metabolic disorders resulting in build-up of endogenous waste and progressive organ damage, can be treated with intravenous enzyme replacement therapy (ERT). ERT can be administered either in specialized clinics, at a physician's office or in the home care setting. Legislative goals in Germany strive to shift to more outpatient care while maintaining treatment objectives. This study investigates the patient perspective on home-based ERT in terms of acceptance, safety, and treatment satisfaction in LSD patients.

Methods

This was a longitudinal observational study, carried out under real-world conditions in patients' home environment, covering 30 months from January 2019 to June 2021. Patients with LSDs who were deemed suitable for home-based ERT by their physicians were recruited to the study. Patients were interviewed before the start of the first home-based ERT and then at regular intervals thereafter using standardized questionnaires.

Results

Data from 30 patients were analyzed: 18 with Fabry disease, 5 with Gaucher disease, 6 with Pompe disease and 1 with Mucopolysaccharidosis type I (MPS I). Age ranged from 8 to 77 years (mean age 40). The reported average waiting time prior to infusion of more than half an hour decreased from 30% of the patients affected at baseline to 5% across all follow-up time points. All patients felt adequately informed about home-based ERT throughout follow-ups and reported that they would choose home-based ERT again. At almost each time point, patients indicated that home-based ERT had improved their ability to cope with the disease. All but one patient indicated feeling safe at each follow-up time point. Compared to 36.7% at baseline, only 6.9% of patients reported a need for improvement in their care after 6 months of home-based ERT. Mean treatment satisfaction increased by approximately 1.6 scale points after 6 months of home-based ERT compared to baseline, and by another 0.2 scale points after 18 months. In terms of quality of care, all but one patient rated home-based ERT as an equivalent alternative throughout follow-ups. Patients would recommend home-based ERT to other suitable LSD-patients.

Conclusion

Home-based ERT increases patients' treatment satisfaction, and patients perceive the quality of care as an equivalent alternative, compared to ERT in a center, clinic, or at a physician's office.

Enzyme replacement therapy in two patients with classic Fabry disease from the same family tree: Two case reports

BACKGROUND

The pathophysiology of Fabry disease (FD)-induced progressive vital organ damage is irreversible. Disease progression can be delayed using enzyme replacement therapy (ERT). In patients with classic FD, sporadic accumulation of globotriaosylceramide (GL-3) in the heart and kidney begins in utero; however, until childhood, GL-3 accumulation is mild and reversible and can be restored by ERT. The current consensus is that ERT initiation during early childhood is paramount. Nonetheless, complete recovery of organs in patients with advanced FD is challenging.

CASE SUMMARY

Two related male patients, an uncle (patient 1) and nephew (patient 2), presented with classic FD. Both patients were treated by us. Patient 1 was in his 50s, and ERT was initiated following end-organ damage; this was subsequently ineffective. He developed cerebral infarction and died of sudden cardiac arrest. Patient 2 was in his mid-30s, and ERT was initiated when the patient was diagnosed with FD, during which the damage to vital organs was not overtly apparent. Although he had left ventricular hypertrophy at the beginning of this treatment, the degree of hypertrophy progression was limited to a minimal range after > 18 years of ERT.

CONCLUSION

We obtained discouraging ERT outcomes for older patients but encouraging outcomes for younger adults with classic FD.

Prevalence of Fabry disease-causing variants in the UK Biobank

BACKGROUND

Fabry disease is an X-linked lysosomal storage disorder resulting from deficiency of the alpha-galactosidase A enzyme leading to accumulation of globotriaosylceramide in multiple organ sites with prominent cardiovascular and renal involvement. Global prevalence estimates of Fabry disease based on clinical ascertainment range from 1 in 40 000 to 1 in 170 000. We aimed to determine the prevalence of Fabry disease-causing variants in UK Biobank.

METHODS

We sought GLA gene variants in exome sequencing data from 200 643 individuals from UK Biobank. We used ACMG/AMP guidelines (American College of Medical Genetics/Association for Molecular Pathology) to classify pathogenicity and compared baseline biomarker data, hospital ICD-10 (International Classification of Diseases version-10) codes, general practitioner records and self-reported health data with those without pathogenic variants.

RESULTS

We identified 81 GLA coding variants. We identified eight likely pathogenic variants on the basis of being rare (<1/10 000 individuals) and either previously reported to cause Fabry disease, or being protein-truncating variants. Thirty-six individuals carried one of these variants. In the UK Biobank, the prevalence of likely pathogenic Fabry disease-causing variants is 1/5732 for late-onset disease-causing variants and 1/200 643 for variants causing classic Fabry disease.

CONCLUSION

Fabry disease-causing GLA variants are more prevalent in an unselected population sample than the reported prevalence of Fabry disease. These are overwhelmingly variants associated with later onset. It is possible the prevalence of later-onset Fabry disease exceeds current estimates.

Coronary microvascular disease in hypertrophic and infiltrative cardiomyopathies

Pathologic hypertrophy of the cardiac muscle is a commonly encountered phenotype in clinical practice, associated with a variety of structural and non-structural diseases. Coronary microvascular disease is considered to play an important role in the natural history of this pathological phenotype. Non-invasive imaging modalities, most prominently positron emission tomography and cardiac magnetic resonance, have provided insights into the pathophysiological mechanisms of the interplay between hypertrophy and the coronary microvasculature. This article summarizes the current knowledge on coronary microvascular dysfunction in the most frequently encountered forms of pathologic hypertrophy.

A Case of Fabry Disease With Lacrimal Gland Involvement

Fabry disease is an X-linked lysosomal storage disease resulting from an error in the glycosphingolipid metabolic pathway, which leads to accumulation of globotriaosylceramide in lysosomes of the skin, kidneys, heart, brain, and other organs. There are no existing reports of histologically proven lacrimal gland involvement in Fabry disease. The authors report the case of a 26-year-old male with Fabry disease who presented with bilateral upper eyelid dermatochalasis, steatoblepharon, and prolapsed lacrimal glands. The patient underwent surgical repair of the upper eyelids and biopsy of the lacrimal glands. The pathologic assessment demonstrated lamellated intracytoplasmic inclusions characteristic of Fabry disease. The prevalence of globotriaosylceramide lacrimal gland deposition in Fabry disease and the effect on lacrimal gland morphology and function have yet to be determined.

Treatment of Fabry Disease: Established and Emerging Therapies

Fabry disease (FD) is a rare, X-linked inherited disorder of glycosphingolipid metabolism. It leads to the progressive accumulation of globotriaosylceramide within lysosomes due to a deficiency of α-galactosidase A enzyme. It involves multiple organs, predominantly the renal, cardiac, and cerebrovascular systems. Early diagnosis and treatment are critical to prevent progression to irreversible tissue damage and organ failure, and to halt life-threatening complications that can significantly reduce life expectancy. This review will focus on the established and emerging treatment options for FD.

Cardiac MRI in Fabry disease

Fabry disease is a rare, progressive X-linked inherited disorder of glycosphingolipid metabolism due to a deficiency of α-galactosidase A enzyme. It leads to the accumulation of globotriaosylceramide within lysosomes of multiple organs, predominantly the vascular, renal, cardiac, and nervous systems. Fabry cardiomyopathy is characterized by increased left ventricular wall thickness/mass, functional abnormalities, valvular heart disease, arrhythmias, and heart failure. Early diagnosis and treatment are critical to avoid cardiac or renal complications that can significantly reduce life expectancy in untreated FD. This review will focus on the role of cardiovascular magnetic resonance imaging in the diagnosis, clinical decision-making, and monitoring of treatment efficacy.

Aseptic meningitis in Fabry disease due to a novel GLA variant: an expanded phenotype?

BACKGROUND

F abry disease (FD) is an X-linked lysosomal storage disorder with accumulation of globotriosylceramide, causing neurologic involvement mainly as acroparesthesias and cerebrovascular disease. Aseptic meningitis has been reported in 11 patients with FD, but no prior study has correlated alpha-galactosidase (GLA) specific variants with meningitis. We present in this manuscript a family in which a novel GLA pathogenic variant was associated with aseptic meningitis in 2 of 5 family members.

METHODS

This study began with identifying the proband, then screening family members for FD symptoms and evaluating symptomatic individuals for genetic and biochemical status. All patients underwent magnetic resonance imaging, and those with headache underwent cerebrospinal fluid (CSF) analysis.

RESULTS

Five patients (3 females) from a single family were included in this study. Mean age at diagnosis was 20.6 years. Two patients (40%) had aseptic meningitis; one of them also had cerebrovascular events. C-reactive protein and erythrocyte sedimentation rate were elevated during aseptic meningitis episodes. Both patients responded to intravenous methylprednisolone with resolution of fever, headache, and vomiting. One of them recurred and needed chronic immunosuppression with azathioprine.

CONCLUSION

We described aseptic meningitis in a family with a novel GLA variant. Meningitis might be a common phenomenon in FD and not a particularity of this variant. Understanding the mechanisms underlying meningitis and its association with cerebrovascular events may lead to a new paradigm of treatment for stroke in these patients. Further prospective studies with CSF collection in patients with FD and recurrent headache could help to elucidate this question.

Systematic cascade screening in the Danish Fabry Disease Centre: 20 years of a national single-centre experience

The lysosomal storage disorder Fabry disease is caused by deficient or absent activity of the GLA gene enzyme α-galactosidase A. In the present study we present the molecular and biochemical data of the Danish Fabry cohort and report 20 years' (2001-2020) experience in cascade genetic screening at the Danish National Fabry Disease Center. The Danish Fabry cohort consisted of 26 families, 18 index patients (9 males and 9 females, no available data for 8 index-patients) and 97 family members with a pathogenic GLA variant identified by cascade genetic testing (30 males and 67 females). Fourteen patients (5 males and 9 females; mean age of death 47.0 and 64.8 years respectively) died during follow-up. The completeness of the Fabry patient identification in the country has resulted in a cohort of balanced genotypes according to gender (twice number of females compared to males), indicating that the cohort was not biased by referral, and further resulted in earlier diagnosis of the disease by a lower age at diagnosis in family members compared to index-patients (mean age at diagnosis: index-patients 42.2 vs. family members 26.0 years). Six previously unreported disease-causing variants in the GLA gene were discovered. The nationwide screening and registration of Fabry disease families provide a unique possibility to establish a complete cohort of Fabry patients and to advance current knowledge of this inherited rare lysosomal storage disorder.

Fabry Disease: Report of Two Cases with Uncommon Presentation

Fabry disease (FD) is a rare, lysosomal storage disorder characterized by multiorgan accumulation of predominantly globotriaosylceramide (GL3) and its metabolite. Resulting renal, cardiac, and cerebrovascular complications are crucial causes of morbidity and mortality in FD. Enzyme replacement therapy (ERT) shows promising outcomes for these patients, provided that therapy is initiated early. Thus, precise and early diagnosis of the disease is a pivotal factor determining the corollary of the disease. We report two cases of young adult males who presented to the nephrology department with proteinuria. A kidney biopsy was performed in both cases, which was suggestive of FD. The final conclusive diagnosis of FD was provided by electron microscopy.

Rare lysosomal disease registries: lessons learned over three decades of real-world evidence

Lysosomal storage disorders (LSD) are rare diseases, caused by inherited deficiencies of lysosomal enzymes/transporters, that affect 1 in 7000 to 1 in 8000 newborns. Individuals with LSDs face long diagnostic journeys during which debilitating and life-threatening events can occur. Clinical trials and classical descriptions of LSDs typically focus on common manifestations, which are not representative of the vast phenotypic heterogeneity encountered in real-world experience. Additionally, recognizing that there was a limited understanding of the natural history, disease progression, and real-world clinical outcomes of rare LSDs, a collaborative partnership was pioneered 30 years ago to address these gaps. The Rare Disease Registries (RDR) (for Gaucher, Fabry, Mucopolysaccharidosis type I, and Pompe), represent the largest observational database for these LSDs. Over the past thirty years, data from the RDRs have helped to inform scientific understanding and the development of comprehensive monitoring and treatment guidelines by creating a framework for data collection and establishing a standard of care, with an overarching goal to improve the quality of life of affected patients. Here, we highlight the history, process, and impact of the RDRs, and discuss the lessons learned and future directions.

Neurological Manifestations of Fabry Disease: Literature Review

BACKGROUND: Fabry disease (FD) or Anderson FD is a hereditary disease belonging to the group of lysosomal storage diseases caused by decreased or absent activity of the enzyme α-galactosidase A. Enzyme deficiency leads to accumulation of glycospholipids in the lysosomes of cells of various organs, including the heart, kidneys, nervous system, and vascular endothelium. The complexity of the diagnosis of FD is due to the variety of its symptoms, the simultaneous involvement of many organs and systems. At present, possible pathogenetic treatment of the disease is enzyme replacement therapy, but its effectiveness is reduced in the later stages of the disease, when there are irreversible abnormal changes in vital organs and systems. In this regard, an urgent task is the early diagnosis of FD. AIM: Determination of neurological manifestations of FD as well as clinical criteria for screening for FD. MATERIALS AND METHODS: We analyzed cohort studies, randomized controlled trials, systematic reviews and meta-analyses, case-control studies, and case series from scientific medical databases: PubMed, Web of Science, Google Scholar in Russian, and English languages. CONCLUSION: The authors found that lesions of the nervous system in FD are detected in more than 80% of patients and can manifest as isolated or combined lesions of both the central and peripheral and autonomic nervous systems.

Quality of life in patients with Fabry's disease: a cross-sectional study of 86 adults

Background

Fabry disease (FD) is a multi-organ disorder associated with severe physical and psychological impairments, particularly in adulthood. To date, comprehensive data on the psychological burden of FD are lacking. The present study assessed quality of life (QOL) in a representative cohort of adults with FD.

Methods

Patient-reported outcome measures were retrospectively analyzed in 86 adults with FD (49.6±16.6 years; 62.8% female) and compared to adults with congenital heart defects (ACHD) which is another lifelong disease and affliction. QOL was assessed using the European Quality of Life 5 Dimensions 5 Levels questionnaire (EQ-5D-5L).

Results

Subjects affected by FD reported an overall reduced QOL (EQ-VAS: 71.8±20.0). Most frequently reported complaints occurred within the dimensions pain/discomfort (69.7%), daily activities (48.9%) and anxiety/depression (45.4%). Compared to ACHD, individuals with FD scored significantly lower in the areas of pain/discomfort, usual activities and mobility (all P<0.05). Older age and female sex were particularly associated with diminished QOL (P=0.05).

Conclusions

Patients with FD are at high risk for impaired QOL. They require additional support to cope with disease-related challenges. Increased attention should be directed towards improving their subjective well-being to potentially increase their QOL and long-term health outcomes.

Burden associated with Fabry disease and its treatment in 12-15 year olds: results from a European survey

Background

Fabry Disease (FD) is a rare X-linked metabolic lysosomal disorder. FD has a broad range of symptoms which vary markedly between patients. The heterogenous nature of the disease makes diagnosis difficult for health care professionals (HCPs), which in turn has a significant effect on the patient’s quality of life (QoL). As few adolescent patients are eligible for treatment, to date there has been little published data on the burden of disease and impact of treatment on these patients and their caregivers. This study was developed to provide some insight into these groups.

Methods

An online-based survey was performed to gather further insights on the burden of FD in 14 adolescents aged 12–15 years old across three European countries, from the perspective of the patients, caregivers and HCPs.

Results

Symptom burden was found to be high in the adolescent population, with ‘pain’ and ‘intolerance to heat or cold’ commonly reported symptoms, both by patients and to HCPs. Eleven of the 14 patients surveyed were receiving enzyme replacement therapy (ERT), with their post-ERT symptomology showing improvement when compared to symptoms before receiving ERT. The majority of caregivers believe their child’s overall health has improved since starting ERT. While there was a positive outlook towards ERT noted by the patients and caregivers, 4/5 HCPs believed there is ‘a need for more efficacious treatment options’ and all HCPs noted that there is ‘a need for more manageable treatment options’. FD was shown to place a burden on caregivers, who reported feelings of guilt and absences from work.

Conclusions

Data show there is a significant symptom burden for the adolescent, which affects their QoL and mental health, as well as placing a burden on the wider family. While ERT is an effective treatment and provides symptom relief for many of the respondents in the survey, they still reported symptom burden. Additionally, there was reporting of reluctance to engage in treatment or difficulties associated with the treatment. Heterogeneity in symptom presentation suggests that the treatment regimen needs to be tailored to the individual. Physicians therefore need to have a choice of treatment options available to help them manage symptoms and disease where the benefit to risk ratio is in favour of undergoing treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02417-3.

The Effect of Green Tea as an Adjuvant to Enzyme Replacement Therapy on Oxidative Stress in Fabry Disease: A Pilot Study

Enzymatic replacement therapy (ERT) is not very effective in halting the progression of Fabry disease (FD) toward cardiovascular (CV)-renal remodeling, particularly in case of late diagnosis. FD patients have increased oxidative stress (OS), critical for the induction of CV-renal remodeling. We investigated the effects of an adjuvant antioxidant treatment to ERT on OS and the possible advantages for related complications. OS was evaluated in 10 patients with FD before ERT, after 12 months of ERT, and after 6 months of adjuvant green tea (GT) to ERT by the following experiments: expression of p22^phox; phosphorylation state of MYPT-1 and ERK 1/2 (by western blotting); and quantification of malondialdehyde (MDA) and heme oxygenase (HO)-1 levels (by ELISA). p22^phox and MYPT-1 phosphorylation decreased after ERT and significantly further decreased after GT. ERK 1/2 phosphorylation and MDA levels remained unchanged after ERT, but significantly decreased after GT. HO-1 significantly increased after ERT and further increased after GT. This study provides preliminary data highlighting the antioxidant effect exerted by ERT itself, further amplified by the adjuvant antioxidant treatment with GT. The results of this study provide evidence of the positive effect of early additive antioxidant treatment to reduce OS and prevent/alleviate cardio and cerebrovascular-renal complications related to OS.

Newborn screening for Fabry disease in Oregon: Approaching the iceberg of A143T and variants of uncertain significance

Fabry disease newborn screening (NBS) has been ongoing in Oregon for over 41 months by first-tier enzyme quantitation and second-tier DNA testing. During that period the majority of abnormal referrals received (34/60) were for the presence of the controversial c.427G > A (p.Ala143Thr) aka A143T and the majority of non-A143T referrals were for other variants of uncertain significance (17/60) resulting in at least 32 infants with an inconclusive case outcome even after clinical evaluation and/or diagnostic testing. To date there has been no significant family history or onset of symptoms in individuals with an inconclusive outcome. Based on our experience, we have developed a framework for approaching A143T and other variants of uncertain clinical significance in an attempt to balance sensitivity with the unnecessary medicalization of healthy infants.

Understanding and modifying Fabry disease: Rationale and design of a pivotal Phase 3 study and results from a patient-reported outcome validation study

The use of available treatments for Fabry disease (FD) (including enzyme replacement therapy [ERT]) may be restricted by their limited symptom improvement and mode of administration. Lucerastat is currently being investigated in the MODIFY study as oral substrate reduction therapy for the treatment of FD. By reducing the net globotriaosylceramide (Gb3) load in tissues, lucerastat has disease-modifying potential to improve symptoms and delay disease progression.

MODIFY is a multicenter, double-blind, randomized, placebo-controlled, parallel-group Phase 3 study (ClinicalTrial.gov: NCT03425539); here we present the rationale and design of this study. Eligible adults with a genetically confirmed diagnosis of FD and FD-specific neuropathic pain entered screening. Patients were randomized (2:1) to receive either oral lucerastat twice daily or placebo for 6 months; treatment allocation was stratified according to sex and ERT treatment status. The main objectives of MODIFY are to assess the effects of lucerastat on neuropathic pain, gastrointestinal (GI) symptoms, FD biomarkers, and determine its safety and tolerability.

Neuropathic pain and GI symptoms are key features of FD that have a significant impact on quality of life. Despite various tools available to assess pain and GI symptoms, there are currently limited tools available to assess neuropathic and GI symptoms in FD, validated according to health authority guidelines. Based on FDA recommendations, we undertook a patient-reported outcome (PRO) validation study, using a novel eDiary-based PRO tool to assess the validity of evaluating neuropathic pain as a primary efficacy endpoint in MODIFY. Results from the PRO validation study are included.

To date, MODIFY is the largest Phase 3 clinical study conducted in patients with FD. Enrollment to MODIFY is now complete, with 118 patients randomized. Results will be presented in a separate publication. Long-term effects of lucerastat are being assessed in the ongoing open-label extension study (NCT03737214).

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There remains a need for treating patients with Fabry disease.

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MODIFY investigated lucerastat as substrate reduction therapy for Fabry disease.

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Limited tools are available to assess neuropathic and GI symptoms in Fabry disease.

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MODIFY assessed neuropathic pain and GI symptoms as primary and secondary efficacy endpoints.

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MODIFY used FDA-recommended validated tools for primary and secondary efficacy endpoints.

Sex-Related Differences in Genetic Cardiomyopathies

Cardiomyopathies are a heterogeneous collection of diseases that have in common primary functional and structural abnormalities of the heart muscle, often genetically determined. The most effective categorization of cardiomyopathies is based on the presenting phenotype, with hypertrophic, dilated, arrhythmogenic, and restrictive cardiomyopathy as the prototypes. Sex modulates the prevalence, morpho-functional manifestations and clinical course of cardiomyopathies. Aspects as diverse as ion channel expression and left ventricular remodeling differ in male and female patients with myocardial disease, although the reasons for this are poorly understood. Moreover, clinical differences may also result from complex societal/environmental discrepancies between sexes that may disadvantage women. This review provides a state-of-the-art appraisal of the influence of sex on cardiomyopathies, highlighting the many gaps in knowledge and open research questions.

Divergent Impact of Enzyme Replacement Therapy on Human Cardiomyocytes and Enterocytes Affected by Fabry Disease: Correlation with Mannose-6-phosphate Receptor Expression

Background: The impact of enzyme replacement therapy (ERT) on cardiomyocytes and intestinal cells, affected by Fabry disease (FD), is still unclear. Methods: Six patients with FD, including five family members with GLA mutation c.666delC and one with GLA mutation c.658C > T, manifesting cardiomyopathy and intestinal symptoms (abdominal pain, diarrhea and malabsorption) were included in the study. Clinical outcome, cardiac magnetic resonance (CMR), endomyocardial and gastro-intestinal biopsies were evaluated before and after 2 years of treatment with agalsidase-α (0.2 mg/kg every other week). Immunohistochemistry and Western blot assessments of mannose-6-phosphate receptors (IGF-II-R) on intestinal and myocardial frozen tissue were obtained at diagnosis and after 2 years of ERT. Results: After ERT left ventricular maximal wall thickness, ranging from pre (<10.5 mm) to mild (<15 mm) and moderate hypertrophy (16 mm), was not associated with significant changes at CMR. Degree of dyspnea, mean cardiomyocyte diameter and % vacuolated areas of cardiomyocytes, representing intracellular GL3, remained unmodified. In contrast, intestinal symptoms improved with disappearance of diarrhea, recovery of anemia and weight gain, correlating with near complete clearance of the enterocytes from GL3 inclusions. IGF-II-R expression was remarkably higher even at histochemistry in intestinal tissue compared with myocardium (p < 0.001) either at baseline and after ERT, thus justifying intestinal recovery. Conclusions: Human cells affected by FD may respond differently to ERT: while cardiomyocytes retain their GL3 content after 2 years of treatment, gastro-intestinal cells show GL3 removal with recovery of function. This divergent response may be related to differences in cellular turnover, as well as tissue IGF-II-R expression.

A new approach to identifying patients with elevated risk for Fabry disease using a machine learning algorithm

Background

Fabry disease (FD) is a rare genetic disorder characterized by glycosphingolipid accumulation and progressive damage across multiple organ systems. Due to its heterogeneous presentation, the condition is likely significantly underdiagnosed. Several approaches, including provider education efforts and newborn screening, have attempted to address underdiagnosis of FD across the age spectrum, with limited success. Artificial intelligence (AI) methods present another option for improving diagnosis. These methods isolate common health history patterns among patients using longitudinal real-world data, and can be particularly useful when patients experience nonspecific, heterogeneous symptoms over time. In this study, the performance of an AI tool in identifying patients with FD was analyzed. The tool was calibrated using de-identified health record data from a large cohort of nearly 5000 FD patients, and extracted phenotypic patterns from these records. The tool then used this FD pattern information to make individual-level estimates of FD in a testing dataset. Patterns were reviewed and confirmed with medical experts.

Results

The AI tool demonstrated strong analytic performance in identifying FD patients. In out-of-sample testing, it achieved an area under the receiver operating characteristic curve (AUROC) of 0.82. Strong performance was maintained when testing on male-only and female-only cohorts, with AUROCs of 0.83 and 0.82 respectively. The tool identified small segments of the population with greatly increased prevalence of FD: in the 1% of the population identified by the tool as at highest risk, FD was 23.9 times more prevalent than in the population overall. The AI algorithm used hundreds of phenotypic signals to make predictions and included both familiar symptoms associated with FD (e.g. renal manifestations) as well as less well-studied characteristics.

Conclusions

The AI tool analyzed in this study performed very well in identifying Fabry disease patients using structured medical history data. Performance was maintained in all-male and all-female cohorts, and the phenotypic manifestations of FD highlighted by the tool were reviewed and confirmed by clinical experts in the condition. The platform’s analytic performance, transparency, and ability to generate predictions based on existing real-world health data may allow it to contribute to reducing persistent underdiagnosis of Fabry disease.

Autopsy Findings of Heterozygous Fabry Disease with the Severe Phenotype: A Case Report

Fabry disease (FD) is an inherited X-linked lysosomal storage disorder, with hemizygous males being more severely affected than heterozygous females. Herein, we report a rare case of FD in a heterozygous female with a severe phenotype. The patient had obesity and hyperlipidemia and had her first cerebral infarction at the age of 33 years. She underwent renal biopsy and was diagnosed with FD with morphological features of focal segmental glomerulosclerosis nephropathy at the age of 34 years. Her leukocyte alpha-galactosidase A activity was 2.3 Agal/U (normal: >20 Agal/U), and genetic analysis revealed the presence of the classical phenotype. Enzyme replacement therapy (ERT) was initiated at the age of 35 years; however, peritoneal dialysis owing to end-stage renal failure occurred at the age of 37 years. The patient died of a cerebral hemorrhage at the age of 44 years. Her Mainz Severity Score Index at the time of death was 48/76, suggestive of the severe phenotype. Autopsy findings revealed remarkable globotriaosylceramide accumulation on electron microscopy, particularly in the major organs and their vascular smooth muscle cells. Regarding the vertebral arteries which sourced the cerebral hemorrhage, the effects of FD-induced vascular thickening and long-term renal failure-induced atherosclerosis were confirmed. Furthermore, the patient's vascular sclerosis was modified with acquired factors such as lifestyle-related disease associated with obesity. We recommend intensified treatment for metabolic factors simultaneous with ERT to help in delaying the progression of FD.

Mechanisms of Neutralizing Anti-drug Antibody Formation and Clinical Relevance on Therapeutic Efficacy of Enzyme Replacement Therapies in Fabry Disease

Fabry disease (FD) is a rare X-linked lysosomal storage disorder caused by mutations in the α-galactosidase A (AGAL/GLA) gene. The lysosomal accumulation of the substrates globotriaosylceramide (Gb₃) and globotriaosylsphingosine (lyso-Gb₃) results in progressive renal failure, cardiomyopathy associated with cardiac arrhythmia, and recurrent strokes, significantly limiting life expectancy in affected patients. Current treatment options for FD include recombinant enzyme-replacement therapies (ERTs) with intravenous agalsidase-α (0.2 mg/kg body weight) or agalsidase-β (1 mg/kg body weight) every 2 weeks, facilitating cellular Gb₃ clearance and an overall improvement of disease burden. However, ERT can lead to infusion-associated reactions, as well as the formation of neutralizing anti-drug antibodies (ADAs) in ERT-treated males, leading to an attenuation of therapy efficacy and thus disease progression. In this narrative review, we provide a brief overview of the clinical picture of FD and diagnostic confirmation. The focus is on the biochemical and clinical significance of neutralizing ADAs as a humoral response to ERT. In addition, we provide an overview of different methods for ADA measurement and characterization, as well as potential therapeutic approaches to prevent or eliminate ADAs in affected patients, which is representative for other ERT-treated lysosomal storage diseases.

Human kidney organoids reveal the role of glutathione in Fabry disease

Fabry disease is an X-linked lysosomal storage disease caused by a mutation in the galactosidase alpha (GLA) gene. Despite advances in therapeutic technologies, the lack of humanized experimental models of Fabry disease has limited the development of new therapies to cure the disease. Herein, we modeled Fabry disease using human inducible pluripotent stem cell (iPSC)-derived kidney organoids and the CRISPR-Cas9 genome-editing system. GLA-mutant human kidney organoids revealed deformed podocytes and tubular cells with accumulation of globotriaosylceramide (Gb3). Ultrastructural analysis showed abundant electron-dense granular deposits and electron-dense lamellate lipid-like deposits that formed concentric bodies (zebra bodies) in the cytoplasm of podocytes and tubules. The oxidative stress level was increased in GLA-mutant kidney organoids, and the increase was accompanied by apoptosis. Enzyme replacement treatment (ERT) with recombinant human α-Gal A decreased the Gb3 accumulation and oxidative stress, which resulted in amelioration of the deformed cellular structure of the GLA-mutant kidney organoids. Transcription profile analyses showed decreased glutathione (GSH) metabolism in GLA-mutant kidney organoids. GSH replacement treatment decreased oxidative stress and attenuated the structural deformity of the GLA-mutant kidney organoids. GSH treatment also increased the expression of podocyte and tubular markers and decreased apoptosis. In conclusion, GLA-mutant kidney organoids derived from human iPSCs are valuable tools for studying the mechanisms and developing novel therapeutic alternatives for Fabry disease.

Early clinical signs in lysosomal diseases

Background and aim

The lysosomal storage diseases are a group of monogenic diseases with multisystemic impairment and chronic progression induced by the deficiency of lysosomal acid hydrolases involved in the breakdown of various macromolecules. The accumulation occurs in the macrophages of the reticule-endothelial system and causes enlargement and functional impairment. The mainly involved organs are the brain, liver, spleen, bones, joints, airways, lungs, and heart. The aim of this study was to evaluate early symptoms, signs and the delay in the diagnosis of different lysosomal diseases.

Methods

The medical documentation of 188 patients with lysosomal storage disorders, aged 1-70 years, were analyzed. All these patients were specifically diagnosed, by enzyme and molecular assay.

Results

The age of clinical signs onset varies in different type of lysosomal diseases, from the first months of life or early childhood in severe form, to adulthood in attenuated forms. The delay between the clinical signs onset and specific diagnosis ranged from 0.5 months to 57.91 years.

Conclusions

The lysosomal storage diseases are rare diseases with childhood onset, but these early signs and symptoms are not recognized and are often taken into account when the vital organs damage becomes manifest.

First 2 Fabry Cases with Novel Mutation and Their Associated Clusters in Malaysia

BACKGROUND No cases of Fabry disease (FD) have been reported thus far in Malaysia. We aimed to report the demographic characteristics, clinical manifestations, molecular results, and treatment outcomes of 2 FD cases. This study was a retrospective review of 2 family clusters of FD on follow-up in Sarawak, Malaysia. CASE REPORT Two index patients were confirmed to have FD. Index patient 1, who had nephrotic-range proteinuria and cornea verticillata, carried a variant within exon 4 of the GLA gene: c.610 T>C (p.Trp204Arg). Agalsidase beta (Fabrazyme®) enzyme replacement therapy was initiated, with the absence of neutralizing antibody after 24 months. No hypersensitivity or adverse reactions were reported. The patient's proteinuria and renal function remained stable. Other family members who carried the same mutation were asymptomatic. Index patient 2, who had residual activity of alpha-galactosidase A and a normal globotriaosylsphingosine level, carried a novel GLA mutation of c.548-5T>A. He was diagnosed with end-stage renal disease on regular dialysis and had nonspecific headache with 1 episode of seizure a few years prior to FD genetic screening. One brother had chronic neuropathic pain but refused further investigations. Other family members who had the same mutation were asymptomatic. This mutation has never been reported in literature, and its pathogenicity warrants further studies. CONCLUSIONS It is of utmost importance to increase awareness of FD among clinicians, so that appropriate screening may be done to determine its true prevalence and prompt treatment can be initiated early.

Precision medicine in Fabry disease

Fabry disease (FD) is a rare X-linked lysosomal storage disorder caused by mutations in the α-galactosidase A (GLA) gene, leading to a deficiency in α-galactosidase A. The lysosomal accumulation of glycosphingolipids, primarily globotriaosylceramide (Gb3) and its deacylated form, globotriaosylsphingosine (lyso-Gb3), results in progressive renal failure, cardiomyopathy associated with cardiac arrhythmia and recurrent cerebrovascular events, significantly limiting life expectancy in affected patients. In male patients, a definitive diagnosis of FD involves demonstrating a GLA deficiency in leucocytes. In females, because of the potential high residual enzymatic activity, the diagnostic gold standard requires molecular genetic analyses. The current treatment options for FD include recombinant enzyme replacement therapies (ERTs) with intravenous agalsidase-α (0.2 mg/kg body weight) or agalsidase-β (1 mg/kg body weight) every 2 weeks as well as an oral pharmacological chaperone (migalastat 123 mg every other day) that selectively and reversibly binds to the active sites of amenable mutant forms of the GLA enzyme. These therapies facilitate cellular Gb3 clearance and an overall improvement of disease burden. However, ERT can lead to infusion-associated reactions, as well as the formation of neutralizing anti-drug antibodies in ∼40% of all ERT-treated males, leading to an attenuation of therapy efficacy. This article reviews the clinical presentation, diagnosis and interdisciplinary clinical management of FD and discusses the therapeutic options, with a special focus on precision medicine, accounting for individual variability in genetic mutations, Gb3 and lyso-Gb3 levels, allowing physicians to predict more accurately which prevention and treatment strategy is best for which patient.

X-chromosome inactivation patterns in females with Fabry disease examined by both ultra-deep RNA sequencing and methylation-dependent assay

BACKGROUND

Fabry disease is an X-linked inherited lysosomal storage disorder caused by mutations in the gene encoding α-galactosidase A. Males are usually severely affected, while females have a wide range of disease severity. This variability has been assumed to be derived from organ-dependent skewed X-chromosome inactivation (XCI) patterns in each female patient. Previous studies examined this correlation using the classical methylation-dependent method; however, conflicting results were obtained. This study was established to ascertain the existence of skewed XCI in nine females with heterozygous pathogenic variants in the GLA gene and its relationship to the phenotypes.

METHODS

We present five female patients from one family and four individual female patients with Fabry disease. In all cases, heterozygous pathogenic variants in the GLA gene were detected. The X-chromosome inactivation patterns in peripheral blood leukocytes and cells of urine sediment were determined by both classical methylation-dependent HUMARA assay and ultra-deep RNA sequencing. Fabry Stabilization Index was used to determine the clinical severity.

RESULTS

Skewed XCI resulting in predominant inactivation of the normal allele was observed only in one individual case with low ⍺-galactosidase A activity. In the remaining cases, no skewing was observed, even in the case with the highest total severity score (99.2%).

CONCLUSION

We conclude that skewed XCI could not explain the severity of female Fabry disease and is not the main factor in the onset of various clinical symptoms in females with Fabry disease.

Fabry disease pain: patient and preclinical parallels

ABSTRACT

Severe neuropathic pain is a hallmark of Fabry disease, a genetic disorder caused by a deficiency in lysosomal α-galactosidase A. Pain experienced by these patients significantly impacts their quality of life and ability to perform everyday tasks. Patients with Fabry disease suffer from peripheral neuropathy, sensory abnormalities, acute pain crises, and lifelong ongoing pain. Although treatment of pain through medication and enzyme replacement therapy exists, pain persists in many of these patients. Some has been learned in the past decades regarding clinical manifestations of pain in Fabry disease and the pathological effects of α-galactosidase A insufficiency in neurons. Still, it is unclear how pain and sensory abnormalities arise in patients with Fabry disease and how these can be targeted with therapeutics. Our knowledge is limited in part due to the lack of adequate preclinical models to study the disease. This review will detail the types of pain, sensory abnormalities, influence of demographics on pain, and current strategies to treat pain experienced by patients with Fabry disease. In addition, we discuss the current knowledge of Fabry pain pathogenesis and which aspects of the disease preclinical models accurately recapitulate. Understanding the commonalities and divergences between humans and preclinical models can be used to further interrogate mechanisms causing the pain and sensory abnormalities as well as advance development of the next generation of therapeutics to treat pain in patients with Fabry disease.

Fabry Disease and the Heart: A Comprehensive Review

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by mutations of the GLA gene that result in a deficiency of the enzymatic activity of α-galactosidase A and consequent accumulation of glycosphingolipids in body fluids and lysosomes of the cells throughout the body. GB3 accumulation occurs in virtually all cardiac cells (cardiomyocytes, conduction system cells, fibroblasts, and endothelial and smooth muscle vascular cells), ultimately leading to ventricular hypertrophy and fibrosis, heart failure, valve disease, angina, dysrhythmias, cardiac conduction abnormalities, and sudden death. Despite available therapies and supportive treatment, cardiac involvement carries a major prognostic impact, representing the main cause of death in FD. In the last years, knowledge has substantially evolved on the pathophysiological mechanisms leading to cardiac damage, the natural history of cardiac manifestations, the late-onset phenotypes with predominant cardiac involvement, the early markers of cardiac damage, the role of multimodality cardiac imaging on the diagnosis, management and follow-up of Fabry patients, and the cardiac efficacy of available therapies. Herein, we provide a comprehensive and integrated review on the cardiac involvement of FD, at the pathophysiological, anatomopathological, laboratory, imaging, and clinical levels, as well as on the diagnosis and management of cardiac manifestations, their supportive treatment, and the cardiac efficacy of specific therapies, such as enzyme replacement therapy and migalastat.