Cornea verticillata and acroparesthesia efficiently discriminate clusters of severity in Fabry disease

Mass cytometry reveals atypical immune profile notably impaired maturation of memory CD4 T with Gb3-related CD27 expression in CD4 T cells in Fabry disease

Fabry disease (FD) is an X-linked disease characterized by an accumulation of glycosphingolipids, notably of globotriaosylceramide (Gb3) and globotriaosylsphingosine (lysoGb3) leading to renal failure, cardiomyopathy, and cerebral strokes. Inflammatory processes are involved in the pathophysiology. We investigated the immunological phenotype of peripheral blood mononuclear cells in Fabry patients depending on the clinical phenotype, treatment, Gb3, and lysoGb3 levels and the presence of anti-drug antibodies (ADA). Leucocytes from 41 male patients and 20 controls were analyzed with mass cytometry using both unsupervised and supervised algorithms. FD patients had an increased expression of CD27 and CD28 in memory CD45- and CD45 + CCR7-CD4 T cells (respectively p < 0.014 and p < 0.02). Percentage of CD45RA-CCR7-CD27 + CD28+ cells in CD4 T cells was correlated with plasma lysoGb3 (r = 0.60; p = 0.0036) and phenotype (p < 0.003). The correlation between Gb3 and CD27 in CD4 T cells almost reached significance (r = 0.33; p = 0.058). There was no immune profile associated with the presence of ADA. Treatment with agalsidase beta was associated with an increased proportion of Natural Killer cells. These findings provide valuable insights for understanding FD, linking Gb3 accumulation to inflammation, and proposing new prognostic biomarkers.

Serum Neopterin, Biopterin, Tryptophan, and Kynurenine Levels in Patients with Fabry Disease

Background

Fabry disease is characterized by the accumulation of globotriaosylceramide. Substrate accumulation in lysosomes is thought to trigger an inflammatory response and is responsible for progressive organ damage through the induction of autoimmunity. The levels of pteridine and kynurenine pathway metabolites increase when immune activation is observed and are employed to monitor several diseases and determine prognosis.

Aims

To elucidate the effects of immune activation on the pathophysiology of Fabry disease and to investigate the potential utility of pteridine and kynurenine metabolites.

Study Design

A prospective case-control study.

Methods

In this study, 33 patients with Fabry disease and 33 age-and sex-matched healthy controls were included. Blood pteridine and kynurenine metabolites were studied in both groups. Organ involvement in Fabry disease and its correlation with the pteridine and kynurenine pathways were also investigated.

Results

The patients’ neopterin and biopterin levels and the tryptophan/kynurenine ratio were statistically higher than those of the healthy control group (p < 0.05). A statistically significant association was found between neopterin levels and hypertrophic cardiomyopathy, cardiac arrhythmias, and GFR values (p = 0.044, p = 0.021, and p = 0.030, respectively), tryptophan and corneal verticillate, hearing loss and tinnitus (p = 0.010, p = 0.009 and p = 0.046, respectively), and kynurenine levels and valvular heart disease (p = 0.020).

Conclusion

From the onset of the disease, patients with Fabry disease exhibited elevated levels of inflammation and immune activation. Furthermore, inflammation and immune activation markers can be used as early disease biomarkers.

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.

Late-onset Fabry disease due to a new (p.Pro380Leu) pathogenic variant of GLA Gene

Fabry disease is a rare X-linked lysosomal storage disorder due to pathogenic variants of the galactosidase alpha (GLA) gene, leading to a deficiency of alpha-galactosidase A. The inadequate enzymatic activity leads to progressive glycosphingolipids accumulation within tissues and subsequent multi-systemic dysfunction, with predominant involvement of heart, kidney, and nervous system. Two subtypes are recognized: the classic type and the late-onset type. We here describe the clinical characteristics of a patient with late-onset Fabry disease carrying a not previously identified GLA gene variant. This 50-year-old man came to hospital because of an acute ischemic stroke. He also complained of acroparesthesia and had angiokeratomas in the nape and the back. Blood alpha-galactosidase A activity was low, plasmatic lyso-Gb3 level was borderline, cardiac MRI showed cardiac fibrosis, brain MRI documented cerebrovascular disease, and skin biopsy revealed small fiber neuropathy without globotriaosylceramide-3 skin deposits. Genetic study by means of targeted next-generation sequencing analysis disclosed a missense substitution c.1139C>T (p.Pro380Leu) in the GLA gene. We suggest that this novel variant should be considered as pathogenic and associated with a late-onset variant of Fabry disease with a predominant neurological phenotype.

Twenty years of the Fabry Outcome Survey (FOS): insights, achievements, and lessons learned from a global patient registry

Background

Patient registries provide long-term, real-world evidence that aids the understanding of the natural history and progression of disease, and the effects of treatment on large patient populations with rare diseases. The year 2021 marks the 20th anniversary of the Fabry Outcome Survey (FOS), an international, multicenter, observational registry (NCT03289065). The primary aims of FOS are to broaden the understanding of Fabry disease (FD), an X-linked lysosomal storage disorder, and to improve the clinical management of affected patients. Here, we review the history of FOS and the analyses and publications disseminated from the registry, and we discuss the contributions FOS studies have made in understanding FD.

Results

FOS was initiated in April 2001 and, as of January 2021, 4484 patients with a confirmed diagnosis and patient informed consent have been enrolled from 144 centers across 26 countries. Data from FOS have been published in nearly 60 manuscripts on a wide variety of topics relevant to FD. Analyses of FOS data have investigated the long-term effectiveness and safety of enzyme replacement therapy (ERT) with agalsidase alfa and its effects on morbidity and mortality, as well as the benefits of prompt and early treatment with agalsidase alfa on the progression of cardiomyopathy and the decline in renal function associated with FD. Based on analyses of FOS data, ERT with agalsidase alfa has also been shown to improve additional signs and symptoms of FD experienced by patients. FOS data analyses have provided a better understanding of the natural history of FD and the specific populations of women, children, and the elderly, and have provided practical tools for the study of FD. FOS has also provided methodology and criteria for assessing disease severity which contributed to the continuous development of medical practice in FD and has largely improved our understanding of the challenges and needs of long-term data collection in rare diseases, aiding in future rare disease real-world evidence studies.

Conclusion

FOS over the last 20 years has substantially increased the scientific knowledge around improved patient management of FD and continues to expand our understanding of this rare disease.

Sphingosine-1-Phosphate Levels Are Higher in Male Patients with Non-Classic Fabry Disease

Fabry disease is an X-linked lysosomal disease in which defects in the alpha-galactosidase A enzyme activity lead to the ubiquitous accumulation of glycosphingolipids. Whereas the classic disease is characterized by neuropathic pain, progressive renal failure, white matter lesions, cerebral stroke, and hypertrophic cardiomyopathy (HCM), the non-classic phenotype, also known as cardiac variant, is almost exclusively characterized by HCM. Circulating sphingosine-1-phosphate (S1P) has controversially been associated with the Fabry cardiomyopathy. We measured serum S1P levels in 41 patients of the FFABRY cohort. S1P levels were higher in patients with a non-classic phenotype compared to those with a classic phenotype (200.3 [189.6−227.9] vs. 169.4 ng/mL [121.1−203.3], p = 0.02). In a multivariate logistic regression model, elevated S1P concentration remained statistically associated with the non-classic phenotype (OR = 1.03; p < 0.02), and elevated lysoGb3 concentration with the classic phenotype (OR = 0.95; p < 0.03). S1P levels were correlated with interventricular septum thickness (r = 0.46; p = 0.02). In a logistic regression model including S1P serum levels, phenotype, and age, age remained the only variable significantly associated with the risk of HCM (OR = 1.25; p = 0.001). S1P alone was not associated with cardiac hypertrophy but with the cardiac variant. The significantly higher S1P levels in patients with the cardiac variant compared to those with classic Fabry suggest the involvement of distinct pathophysiological pathways in the two phenotypes. S1P dosage could allow the personalization of patient management.

Interstitial lung disease in lysosomal storage disorders

Lysosomes are intracellular organelles that are responsible for degrading and recycling macromolecules. Lysosomal storage diseases (LSDs) are a group of inherited diseases caused by mutations affecting genes that encode the function of the lysosomal enzymes. Three LSDs are associated with lung involvement and/or interstitial lung disease (ILD): Gaucher disease (GD); Niemann-Pick disease, also known as acid sphingomyelinase deficiency (ASMD); and Fabry disease (FD). In GD and in ASMD, analysis of bronchoalveolar lavage fluid and lung biopsy can be informative, showing foamy cells. In GD, ILD is rare. Enzyme replacement therapy (ERT) has been available since 1991 and has greatly changed the natural history of GD, with pulmonary failure and death reported before the ERT era. In ASMD, ILD is frequent and is usually associated with spleen enlargement, low platelet cell count and low level of high-density lipoprotein-cholesterol. Results of ERT are promising regarding preliminary results of olipudase alfa in paediatric and adult ASMD populations. The most frequent respiratory manifestation in FD is COPD-like symptoms regardless of smoking habit and dyspnoea due to congestive heart failure. Early diagnosis of these three LSDs is crucial to prevent irreversible organ damage. Early initiation of ERT can, at least in part, prevent organ failure.