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.

Consensus recommendations for the treatment and management of patients with Fabry disease on migalastat: a modified Delphi study.

Objective: Fabry disease is a progressive disorder caused by deficiency of the α-galactosidase A enzyme (α-Gal A), leading to multisystemic organ damage with heterogenous clinical presentation. The addition of the oral chaperone therapy migalastat to the available treatment options for Fabry disease is not yet universally reflected in all treatment guidelines. These consensus recommendations are intended to provide guidance for the treatment and monitoring of patients with Fabry disease receiving migalastat. Methods: A modified Delphi process was conducted to determine consensus on treatment decisions and monitoring of patients with Fabry disease receiving migalastat. The multidisciplinary panel comprised 14 expert physicians across nine specialties and two patients with Fabry disease. Two rounds of Delphi surveys were completed and recommendations on the use of biomarkers, multidisciplinary monitoring, and treatment decisions were generated based on statements that reached consensus. Results: The expert panel reached consensus agreement on 49 of 54 statements, including 16 that reached consensus in round 1. Statements that reached consensus agreement are summarized in recommendations for migalastat treatment and monitoring, including baseline and follow-up assessments and frequency. All patients with Fabry disease and an amenable mutation may initiate migalastat treatment if they have evidence of Fabry-related symptoms and/or organ involvement. Treatment decisions should include holistic assessment of the patient, considering clinical symptoms and organ involvement as well as patient-reported outcomes and patient preference. The reliability of α-Gal A and globotriaosylsphingosine as pharmacodynamic response biomarkers remains unclear. Conclusion: These recommendations build on previously published guidelines to highlight the importance of holistic, multidisciplinary monitoring for patients with Fabry disease receiving migalastat, in addition to shared decision-making regarding treatments and monitoring throughout the patient journey. GRAPHICAL ABSTRACT.

Consenso de expertos sobre recomendaciones basadas en evidencia para el diagnóstico, tratamiento y seguimiento de enfermedad de Fabry en pediatría / Expert Consensus on Evidence-Based Recommendations for the Diagnosis, Treatment, and Follow-Up of Fabry Disease in Pediatric Patients / Consenso de especialistas colombianos sobre recomendações baseadas em evidências para o diagnóstico, tratamento e acompanhamento da doença de Fabry em pediatria

Antecedentes: la enfermedad de Fabry (Ef) es una enfermedad rara ligada a X secundaria al depósito lisosomal de glicoesfingolípidos, debido a la deficiencia de la enzima alfa galactosidasa A (α-Gal A). A pesar de su baja frecuencia, es una condición que afecta la calidad de vida de los pacientes y disminuye su esperanza de vida. Objetivo: generar recomendaciones informadas para el diagnóstico y tratamiento de pacientes pediátricos (menores de 18 años) con Ef. Material y Métodos: revisión de literatura en bases de datos y literatura gris a partir de 2010, incluyendo guías de práctica clínica, revisiones sistemáticas y estudios primarios. La calidad de evidencia se evaluó de acuerdo con el tipo. Las recomendaciones se sometieron a consenso de expertos a través de metodología Delphi modificada. El acuerdo se definió a partir del 80 %. Resultados: A partir del análisis de la evidencia recolectada se formularon un total de 45 recomendaciones para tamización, diagnóstico y tratamiento de paciente pediátrico con Ef. El panel revisor estuvo conformado por once expertos en el tema. Las recomendaciones fueron aprobadas con puntuaciones entre 82.3 % y 100 %. Conclusiones: las recomendaciones resultantes del consenso de expertos permitirán la toma de decisiones clínicas y estandarización de la práctica en la atención de pacientes pediátricos con Ef en el país y la región. El diagnóstico temprano y oportuno garantiza una disminución del impacto en la calidad de vida de los pacientes y sus familiares

Background: Fabry disease (fD) is a rare X-linked disease characterized by the accumulation of glyco- sphingolipids in lysosomes due to the deficiency in the production of alpha-galactosidase A (α-Gal A) enzyme. Despite its low frequency, this disease has a serious impact on the life expectancy and quality. Objective: To make evidence-based recommendations for the diagnosis and treatment of fD in pediatric patients (<18 years of age). Materials and Methods: A study of databases and gray literature was conducted in 2010, including clinical practice guidelines, systematic reviews, and primary research. The type of evidence was used to determine the quality of evidence. The recommendations were submitted to an expert consensus using the modified Delphi process. The agreement was set at 80%. Conclusions: The recommendations emerging from this expert consensus will enable the standardization of care provision for pediatric patients with fD in Colombia and Latin America and clinical decision-making for disease management. Notably, making an early diagnosis ensures a reduction in the impact of this disease on the quality of life of patients and their families

Fundamento: a doença de Fabry (Df) é uma rara doença ligada ao cromossomo X secundária à deposi- ção lisossômica de glicoesfingolipídeos devido à deficiência da enzima alfa galactosidase A (α-Gal A). Apesar de sua baixa frequência, é uma condição que afeta a qualidade de vida dos pacientes e diminui sua expectativa de vida. Objetivo: gerar recomendações baseadas em evidências para o diagnóstico e tratamento de pacientes pediátricos (com menos de 8 anos de idade) com Df. Materais e Métodos: foi realizada uma revisão da literatura em bases de dados e literatura cinza a partir de 2010, incluindo diretrizes de prática clínica, revisões sistemáticas e estudos primários. A qualidade da evidência foi avaliada de acordo com o tipo de evidência. As recomendações foram submetidas ao consenso de especialistas usando a metodologia Delphi modificada. A concordância foi definida a partir de 80%. Resultados: com base na análise das evidências coletadas, foram formuladas um total de 45 recomendações para triagem, diagnóstico e tratamento de pacientes pediátricos com doença de Fabry. O painel de revisão foi composto por onze especialistas no assunto. As recomendações foram aprovadas com pontuações entre 82,3% e 100%. Conclusões: as recomendações resultantes do consenso de especialistas permitirão a tomada de decisão clínica e a padronização da prática no cuidado de pacientes pediátricos com Df em nível nacional e regional; o diagnóstico precoce e oportuno garante a redução do impacto na qualidade de vida dos pacientes e seus familiares.

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.

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).

Consenso colombiano de expertos sobre recomendaciones basadas en evidencias para el diagnóstico, el tratamiento y el seguimiento de la enfermedad de Fabry con compromiso renal

Contexto: la enfermedad de Fabry se comporta como una enfermedad crónica con compromiso multisistémico y alto costo en salud. Objetivo: generar recomendaciones basadas en la evidencia para el diagnóstico, el tratamiento y el seguimiento de la enfermedad de Fabry con compromiso renal mediante un consenso de expertos. Metodología: a partir de la búsqueda de evidencia en Pubmed, Embase y Google Scholar entre 2010 y agosto 2020, se formulan recomendaciones sobre la definición, el diagnóstico y el tratamiento de la enfermedad de Fabry en población adulta, las cuales se consultan a un panel de expertos a través de la metodología de consenso Delphi modificado. La calidad de los documentos se evaluó por equipo metodológico aplicando herramientas en función del tipo de documento incluido. Resultados: se formularon 53 recomendaciones sobre la definición, el diagnóstico y el tratamiento. Un panel de cinco expertos clínicos nacionales e internacionales externos al grupo desarrollador participaron en la consulta preconsenso y 50 recomendaciones fueron acordadas para su inclusión, para tres de ellas se requirió una sesión formal de consenso que se dio en una ronda, incorporando tres nuevas recomendaciones. Conclusiones: las recomendaciones basadas en evidencia y experticia clínica permitirán orientar de manera estandarizada a nivel nacional y regional, el diagnóstico y el tratamiento de pacientes con sospecha o enfermedad de Fabry con compromiso renal.

Background: Fabry disease behaves like a chronic condition, with multisystem involvement and high health care costs. Objective: To generate evidence-based recommendations for the diagnosis, treatment and follow-up of the Anderson-Fabry disease with renal commitment, through an expert consensus. Methodology: Based on the search of evidence in PubMed, Embase and Google Scholar between 2010 and August, 2020, recommendations on the definition, diagnosis and treatment of Fabry Disease in adult population were formulated after consulting with an expert panel through the modified Delphi consensus methodology. The quality of the documents was assessed by methodological team applying tools according to the type of document included. Results: 53 recommendations for the definition, diagnosis and treatment were formulated. A panel of five national and international clinical experts external to the developer group participated in the pre-consensus consultation and 50 recommendations were agreed upon for their inclusion. For 3 recommendations, a formal consensus session which took place in one round was required, and 3 new recommendations were incorporated. Conclusions: The recommendations based on evidence and clinical expertise will allow us to guide the diagnosis and treatment of patients with Fabry disease with renal involvement or suspicion thereof in a standardized manner at national and regional levels.

Fabry Disease Patient-Reported Outcome (FD-PRO) demonstrates robust measurement properties for assessing symptom severity in Fabry disease.

BACKGROUND: Fabry disease (FD) is a rare, genetic disease, that if untreated, progresses to irreversible and life-threatening renal, cardiac, and cerebrovascular events. FD symptoms impact daily functioning and quality of life, but no disease-specific measure of these symptoms has been psychometrically tested. METHODS: The Fabry Disease Patient-Reported Outcome (FD-PRO) consists of 19 items that measure neuropathic symptoms (pain, tingling, numbness and burning in upper/lower extremities), headache, abdominal pain, heat intolerance, swelling, tinnitus, fatigue, hearing/vision impairment, hypohidrosis (diminished sweating) and difficulty engaging in regular physical activities in the past 24 h. Measurement properties of the instrument were evaluated among 139 adult (≥ 18 years) FD diagnosed patients (enzyme deficiency in males; GLA genotyping in females) including enzyme replacement (ERT) treated or treatment-naïve patients, classic or late-onset phenotypes from ten countries and eighteen sites. Patients completed the FD-PRO daily on a handheld electronic diary for 4 weeks; demographic, other patient and clinician reported outcomes were also collected. RESULTS: The mean age of patients was 43 years; with even sex distribution (female: 53%) and majority was ERT treated (72%). Patient compliance was high; ≥ 87% completed at least 4 FD-PRO entries each week (mean completion time: < 3 min in week one). Empirical evaluation of item properties via inter-item correlations, exploratory factor analysis and item-response theory models suggested that a total symptom score (TSS) could be calculated. Due to redundancy among items, a "neuropathy parcel" and an "audiovisual parcel" were created in generating the TSS (items within a parcel averaged and treated as a single item). Two items were excluded from TSS: sweating (did not correlate with other items) and difficulty engaging in regular physical activities (measure of impact, not symptoms). Internal consistency (Cronbach's alpha) of the TSS was ≥0.89 across weeks; test-retest reliability (intraclass correlation coefficient) was ≥0.91. The TSS was correlated with conceptually similar clinical and patient reported assessments as expected (r > |0.4|) and discriminated moderate/severe from least severe FD groups in known-groups validity analyses. CONCLUSIONS: The FD-PRO instrument is a novel disease-specific instrument that assesses classic and non-classic symptoms, with strong psychometric properties and appropriate for use in clinical studies.

The benefits and challenges of family genetic testing in rare genetic diseases-lessons from Fabry disease.

BACKGROUND: Family genetic testing of patients newly diagnosed with a rare genetic disease can improve early diagnosis of family members, allowing patients to receive disease-specific therapies when available. Fabry disease, an X-linked lysosomal storage disorder caused by pathogenic variants in GLA, can lead to end-stage renal disease, cardiac arrhythmias, and stroke. Diagnostic delays are common due to the rarity of the disease and non-specificity of early symptoms. Newborn screening and screening of at-risk populations, (e.g., patients with hypertrophic cardiomyopathy or undiagnosed nephropathies) can identify individuals with Fabry disease. Subsequent cascade genotyping of family members may disclose a greater number of affected individuals, often at younger age than they would have been diagnosed otherwise. METHODS: We conducted a literature search to identify all published data on family genetic testing for Fabry disease, and discussed these data, experts' own experiences with family genetic testing, and the barriers to this type of screening that are present in their respective countries. RESULTS: There are potential barriers that make implementation of family genetic testing challenging in some countries. These include associated costs and low awareness of its importance, and cultural and societal issues. Regionally, there are barriers associated with population educational levels, national geography and infrastructures, and a lack of medical geneticists. CONCLUSION: In this review, the worldwide experience of an international group of experts of Fabry disease highlights the issues faced in the family genetic testing of patients affected with rare genetic diseases.

Enzyme replacement therapy interruption in mucopolysaccharidosis type IVA patients and its impact in different clinical outcomes.

Mucopolysaccharidosis type IVA (MPS IVA) is an autosomal recessive lysosomal storage disorder caused by mutations in the GALNS gene, which leads to deficient activity of N-acetylglucosamine-6-sulfate sulfatase. MPS IVA patients usually present skeletal dysplasia, coarse features, short stature, airway obstruction, cervical spinal cord compression, dental abnormalities, and cardiac valvular alterations. Enzyme replacement therapy (ERT) with elosulfase alfa is the only disease-specific treatment available for MPS IVA patients and has been shown to improve important clinical and biochemical parameters; however, little is known about the effects of ERT interruption on these patients. In this article, we report the impact of different periods of treatment interruption on clinical outcomes of 18 MPS IVA patients. All MPS IVA patients included in this case series were treated and followed up in Latin American centers and had been receiving elosulfase alfa intravenously for at least 8 months before ERT was interrupted. Different clinical parameters and assessments were evaluated at variable timepoints following therapy interruption. Altogether, our report indicates that some beneficial ERT effects in MPS IVA patients may last after different periods of treatment interruption, as cardiac and respiratory function improvements. However, worsening of important disease parameters after ERT interruption, such as the increase in uGAGs, pain, joint and skeletal aspects, and surgery indications suggests that treatment discontinuation should be avoided in order to maintain the disease as stable as possible, aiming to optimize these patients' life expectancy and quality of life.

Improvement of gastrointestinal symptoms in a significant proportion of male patients with classic Fabry disease treated with agalsidase beta: A Fabry Registry analysis stratified by phenotype.

BACKGROUND: Fabry disease is an inherited disorder of glycolipid metabolism with progressive involvement of multiple organs, including the gastrointestinal tract, in classically affected male patients. Clinical presentations in males with later-onset Fabry phenotypes are more heterogeneous and largely dependent on the level of residual α-galactosidase A activity. METHODS: We assessed agalsidase beta treatment outcomes of gastrointestinal symptoms in adult males with classic or later-onset Fabry disease. Self-reports of abdominal pain and diarrhea ('present'/'not present' since previous assessment) at last clinical visit (≥0.5 year of follow-up) were compared with treatment-baseline. RESULTS: Classic male patients were considerably younger at first treatment than the fewer males with later-onset phenotypes (36 vs. ~47 years) and reported gastrointestinal symptoms more frequently at baseline (abdominal pain: 56% vs. 13%; diarrhea: 57% vs. 23%). As compared with baseline, significantly fewer classic patients reported abdominal pain after a median of 4.7 years of treatment (N = 171, 56% vs. 41%, P < 0.001). Moreover, significantly fewer patients reported diarrhea after 5.5 years of follow-up (N = 169, 57% vs. 47%, P < 0.05). Among the males with later-onset phenotypes, albeit statistically non-significant, abdominal pain reports reduced after a median of 4.2 years (N = 48, 13% vs. 4%) and diarrhea reports reduced after a median of 4.4 years of treatment (N = 47, 23% vs. 13%). CONCLUSIONS: Sustained treatment with agalsidase beta was associated with improvement in abdominal pain and diarrhea in a significant proportion of classic male Fabry patients. Males with later-onset phenotypes reported gastrointestinal symptoms much less frequently at baseline as compared with classic patients, and non-significant reductions were observed.

Trasplante renal en la enfermedad de Fabry: una historia de idas y vueltas / Kidney transplant in Fabry disease: a round-trip story

La enfermedad de Fabry es una patología por depósito lisosomal causada por mutaciones en el gen GLA que resulta en la deficiencia de alfa galactosidasa A. Dentro de las complicaciones tardías más comunes se encuentra la insuficiencia renal terminal. Por medio de una revisión bibliográfica en la base PUBMed se busca evidenciar si el trasplante renal representa una opción terapéutica indiscutible para el tratamiento de la nefropatía de Fabry. Hallazgos demuestran la posibilidad de la terapia de reemplazo enzimático que permite proteger al sistema cardiovascular y nervioso del daño progresivo por acumulo lisosomal.

Fabry disease is a lysosomal storage disorder caused by mutations in the GLA gene that results in alpha galactosidase A deficiency. One of the most common late complications is end stage renal disease. Through a bibliographic review in the PUBMed database, we seek to demonstrate whether kidney transplantation represents an indisputable therapeutic option for the treatment of Fabry nephropathy. Findings demonstratethepossibility of enzymereplacementtherapythatprotects the cardiovascular and nervoussystemfromprogressivedamagebylysosomalaccumulation.

Fabry disease during the COVID-19 pandemic. Why and how treatment should be continued.

Fabry disease is an X-linked disease due to a deficiency of the lysosomal enzyme alpha-galactosidase A. Clinical symptoms in classically affected males include acroparesthesia, anhydrosis and angiokeratoma, which may present during childhood followed by cardiac, cerebral and renal complications. Even though pulmonary involvement is not widely appreciated by clinicians, an obstructive lung disease is another recognized component of Fabry disease. Coronavirus Disease-19 (COVID-19), caused by the SARS-CoV-2 virus was labeled as a global pandemic and patients with Fabry disease can be considered at high risk of developing severe complications. The impact of COVID-19 on patients with Fabry disease receiving enzyme replacement therapy is still unknown. Many patients who receive treatment in the hospital experienced infusion disruptions due to fear of infection. Effects of temporary treatment interruption was described in more detail in other lysosomal storage diseases, but the recommencement of therapy does not fully reverse clinical decline due to the temporary discontinuation. When possible, home-therapy seems to be the most efficient way to maintain enzyme replacement therapy access during pandemic. Sentence take-home message: Home-therapy, when possible, seems to be the most efficient way to maintain enzyme replacement therapy access during pandemic in patients with Fabry disease.

Enzyme replacement therapy interruption in patients with Mucopolysaccharidoses: Recommendations for distinct scenarios in Latin America.

BACKGROUND: Mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders, leading to the progressive accumulation of glycosaminoglycans (GAGs) and the subsequent compromising of tissues and organ malfunction. Although incurable, most types of MPS can be treated with enzyme replacement therapy (ERT), an approach that has had positive effects on the natural clinical evolution and which impact has been extensively investigated. Unfortunately, to date, there is relatively little data regarding the effects of ERT interruption, especially in Latin America, where such interruption may be frequent due to a variety of issues (for instance, difficulties involving logistics, reimbursement and/or payment withdrawal). METHOD: A group of medical professionals from Latin America with experience in Genetics, Pediatrics and Neurology held an Advisory Board Meeting in the city of São Paulo, in October 2018, to discuss the issue of ERT interruptions in the region and recommendations health care professionals on how to deal with these interruptions and better assess the therapeutic effects of ERT. CONCLUSION: Recommendations provided by the experts may support physicians in dealing with the most common reasons for ERT interruptions in Latin America. Most importantly, recommendations for data collection at specific timepoints (at baseline, throughout the treatment and during the interruption period of ERT and after its resumption) can significantly improve the collection of real world evidence on the effects of ERT and its interruptions, supporting health care professionals and policy makers in the decision making regarding the provision of these therapies for MPS patients.

Use of a rare disease registry for establishing phenotypic classification of previously unassigned GLA variants: a consensus classification system by a multispecialty Fabry disease genotype-phenotype workgroup.

BACKGROUND: Fabry disease (α-galactosidase deficiency) is an X-linked genetic disease caused by a variety of pathogenic GLA variants. The phenotypic heterogeneity is considerable, with two major forms, classic and later-onset disease, but adjudication of clinical phenotype is currently lacking for many variants. We aimed to determine consensus phenotypic classification for previously unclassified GLA variants from the GLA-specific fabry-database.org database. METHODS: A Fabry disease genotype-phenotype workgroup developed a five-stage iterative system based on expert clinical assessment, published literature and clinical evidence of pathogenicity using a 2-point scoring system based on clinical hallmarks of classic disease. Kaplan-Meier (KM) analysis of severe clinical event-free survival was used as final validation. Results were compared with those from web-based disease databases and in silico pathogenicity prediction programmes. RESULTS: Final consensus on classifications of 'pathogenic' was achieved for 32 of 33 GLA variants (26 'classic' phenotype, 171 males; 6 'later-onset' phenotype, 57 males). One variant remained of uncertain significance. KM curves were similar for the known fabry-database.org database phenotypes and when workgroup consensus classifications were added, and the curves retained the same separation between 'classic' and 'later-onset' phenotypes. CONCLUSION: The iterative system implemented by a Fabry disease genotype-phenotype workgroup achieved phenotypic classifications for variants that were previously unclassified. Clinical pathogenicity associated with a particular GLA variant defined in affected males appears to have predictive value and also generally correlates with risk for affected females. The newly established classifications can be of benefit to the clinical care of Fabry patients harbouring these variants.

Fabry disease and COVID-19: international expert recommendations for management based on real-world experience.

The rapid spread of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 has raised questions about Fabry disease (FD) as an independent risk factor for severe COVID-19 symptoms. Available real-world data on 22 patients from an international group of healthcare providers reveals that most patients with FD experience mild-to-moderate COVID-19 symptoms with an additional complication of Fabry pain crises and transient worsening of kidney function in some cases; however, two patients over the age of 55 years with renal or cardiac disease experienced critical COVID-19 complications. These outcomes support the theory that pre-existent tissue injury and inflammation may predispose patients with more advanced FD to a more severe course of COVID-19, while less advanced FD patients do not appear to be more susceptible than the general population. Given these observed risk factors, it is best to reinforce all recommended safety precautions for individuals with advanced FD. Diagnosis of FD should not preclude providing full therapeutic and organ support as needed for patients with FD and severe or critical COVID-19, although a FD-specific safety profile review should always be conducted prior to initiating COVID-19-specific therapies. Continued specific FD therapy with enzyme replacement therapy, chaperone therapy, dialysis, renin-angiotensin blockers or participation to clinical trials during the pandemic is recommended as FD progression will only increase susceptibility to infection. In order to compile outcome data and inform best practices, an international registry for patients affected by Fabry and infected by COVID-19 should be established.

Perthes-Like Disease Masquerading Non-Classical MPS

Abstract Mucopolysaccharidoses (MPS) are inborn errors of metabolism caused by deficient lysosomal enzymes, leading to organomegaly, hip osteonecrosis, coarse facial features, bone deformities, joint stiffness, cardiac and pulmonary symptoms (MPS VI) or hypermobility (MPS IVA). Some patients may present with non-classical forms of the disease in which osteoarticular abnormalities are the initial symptoms of non-classical forms. As orthopedists and surgeons are the specialists most frequently consulted before the diagnosis, it is critical that MPS may be considered as a differential diagnosis for patients with bone dysplasia. Experts in Latin America reviewed medical records focusing on disease onset, first symptoms and the follow-up clinical and surgical outcomes of non-classical MPS VI and IVA patients. All patients displayed orthopedic issues, which worsened over time, followed by cardiac and ophthalmological abnormalities. Our findings enlighten the necessity of including non-classical MPS as possible diagnosis for patients who report osteoarticular abnormalities in absence of inflammation.

Genotype-Phenotype Variations of Renal Complications in Fabry Disease Q279X Mutation

Abstract In more than 800 GLA gene mutations causing Fabry Disease (FD), renal involvement vary according to the α-GAL A mutation. The aim is to describe the genotype/phenotype variations of renal complications in two siblings with confirmed FD with the mutation p.Q279X in exon 6. We present a retrospective study of two venezuelan male siblings, ages 34 (patient 1) and 33 (patient 2), evaluated by general lab tests, renal ultrasound, renal scintigram , and renal biopsy. Fabry disease diagnose was made by α-galactosidase A activity determined in dried blood spot. Genomic DNA was sequenced by Sanger method. Patient 1 developed CKD grade 5 and high blood pressure, treated by hemodialysis during 8 years. Patient 2 showed GFR >60 ml/min, and proteinuria less than 600 mg/24H. Renal biopsy showed segmental sclerotic lesions and hypertrophic podocytes with vacuolated cytoplasm. Both patients received ERT every two weeks since 2003. Patient 1 died because dialysis complications (hyperparathyroidism, cardiomyopathy). The genotype/phenotype variation of the c.835C>T mutation (p.Gln279Ter. Q279X) in exon 6 of the GLA gene can express an important renal variation with a wide range of clinical manifestations that cannot be predicted, therefore, an early nephrological evaluation and periodic follow-up of these patients are necessary.

The clinical profiles of female patients with Fabry disease in Latin America: A Fabry Registry analysis of natural history data from 169 patients based on enzyme replacement therapy status.

BACKGROUND: Fabry disease is an X-linked lysosomal storage disorder with heterogeneous clinical expression in female patients ranging from asymptomatic to severe clinical presentations as in classic males. We assessed clinical profiles and compared natural history data of female patients eventually initiated on enzyme replacement therapy ("ERT-recipients") with those remaining untreated ("ERT-naïve"). METHODS: We analyzed Fabry Registry data from 93 ERT-recipients, collected prior to ERT initiation, and 76 ERT-naïve females with classic or unclassified phenotypes from four Latin American countries and evaluated Fabry symptoms, interventricular septum thickness, left ventricular posterior wall thickness, estimated glomerular filtration rate, and severe clinical events. RESULTS: For 169 patients with available data, median age of first Fabry symptom manifestation was 12.7 years with peripheral pain as predominant first symptom, and diagnostic delay of 10.3 years from the first reported symptom. Female patients had high symptomatic burden during natural history follow-up, with 83% reporting peripheral pain, 69%-79% cold/heat intolerance or abnormal sweating, and 32% gastrointestinal symptoms. ERT-recipients reported similar age at first symptom as ERT-naïve patients but they were older at diagnosis (median 39.2 vs 24.4 years, P < .01) and last follow-up (median 43.4 vs 28.2 years, P < .01). Reported Fabry symptom frequencies and abnormal echocardiography findings were higher in ERT-recipients. Functional renal assessments were normal and similar. CONCLUSIONS: Female patients from Latin America have notable diagnostic delays and high symptomatic burden. ERT was prescribed late in females with advanced age at diagnosis and advanced disease. There remained many female patients who had been diagnosed at younger age, had substantial Fabry manifestations, but did not receive disease-specific treatment.

Prevalence of Fabry disease in male dialysis patients: Argentinean screening study.

BACKGROUND: Fabry disease (FD) is an X-linked lysosomal storage disorder caused by enzyme Alpha-Galactosidase A (α-Gal-A) deficiency, due mutations in GLA gene. Progressive glycolipid accumulation leads to damage in kidney and other organs. The aim of this study was to estimate the prevalence of Fabry disease in Argentinean male patients undergoing dialysis. METHODS: A prospective screening study was carried out measuring the α-Gal-A activity in dried blood spot (DBS) samples of male patients undergoing dialysis from Argentina. Those patients in which DBS α-Gal-A level was low (<4.0 µmol/hr/L), underwent GLA genetic testing for diagnosis confirmation. RESULTS: Nine thousand six hundred and four dialysis male patients from 264 centers distributed over 20 of the 23 provinces of Argentina were investigated. Twenty-four patients showed a decreased or absent α-Gal-A activity in DBS and although genetic analysis found a variant in the GLA gene in every one of these patients, we could confirm FD diagnosis in 22 cases. CONCLUSION: The prevalence rate of FD found in Argentinean male dialysis patients was 0.23%. Classic phenotype was observed in 73% of patients, whereas the remaining 27% presented as late-onset variant. This was the largest study carried out in dialysis patients from a same country at a worldwide level and the first study performed in Argentina.