A nonsense mutation (R220X) in the alpha-galactosidase A gene causes typical Fabry disease in both genders

Sex Differences in Anderson-Fabry Cardiomyopathy: Clinical, Genetic, and Imaging Analysis in Women

Anderson-Fabry Disease (AFD) is a rare, systemic lysosomal storage disease triggered by mutations in the GLA gene, leading to α-galactosidase A (α-Gal A) deficiency. The disease's X-linked inheritance leads to more severe, early-onset presentations in males, while females exhibit variable, often insidious, manifestations, notably impacting cardiac health. This study aims to examine gender-based AFD cardiac manifestations in correlation with the variant type: classical (CL), late-onset (LO), or variants of uncertain significance (VUS). We analyzed data from 72 AFD patients (53 females, 19 males) referred to the "G. Rodolico" University Hospital, employing enzyme activity measurements, genetic analysis, periodic lyso-Gb3 monitoring, comprehensive medical histories, and advanced cardiac imaging techniques. Statistical analysis was performed using SPSS version 26. Our AFD cohort, with an average age of 45 ± 16.1 years, comprised 12 individuals with hypertrophy (AFD-LVH) and 60 without (AFD-N). Women, representing about 75% of the subjects, were generally older than men (47.2 ± 16.2 vs. 38.8 ± 14.6, p = 0.046). In the female group, 17% had CL variants, 43.3% LO, and 39.6% had VUS, compared to 21.1%, 36.8%, and 31.6% in the male group, respectively. Females exhibited significantly higher α-Gal A values (median 7.9 vs. 1.8 nmol/mL/h, p < 0.001) and lower lyso-Gb3 levels (1.5 [IQR 1.1-1.7] vs. 1.9 [1.5-17.3] nmol/L, p = 0.02). Regarding the NYHA class distribution, 70% of women were in class I and 28% in class II, compared to 84% and 16% of men, respectively. Among women, 7.5% exhibited ventricular arrhythmias (10.5% in men), and 9.4% had atrial fibrillation (10.5% in men). Cardiac MRIs revealed fibrosis in 57% of examined women, compared to 87% of men. Even among patients without LVH, significant differences persisted in α-Gal A and lyso-Gb3 levels (p = 0.003 and 0.04), as well as LVMi (61.5 vs. 77.5 g/sqm, p = 0.008) and GLS values (-20% vs. -17%, p = 0.01). The analysis underscored older age, decreased lyso-Gb3 deposition, reduced hypertrophy, and lesser GLS compromise in females, suggesting later disease onset. Severe cardiac patterns were associated with classic variants, while more nuanced manifestations were noted in those with VUS. Early GLS impairment in males, irrespective of hypertrophy, emphasized the role of subclinical damage in AFD.

Fabry's Disease: The Utility of a Multidisciplinary Screening Approach

(1) Background: As a lysosomal storage disorder, Fabry’s disease (FD) shows variable clinical manifestations. We applied our multidisciplinary approach to identify any organ damage in a sample of adult patients with different pathogenic variants. (2) Methods: 49 participants (mean age 44.3 ± 14.2 years; 37 females), underwent a multidimensional clinical and instrumental assessment. (3) Results: At diagnosis, mean enzymatic activity was 5.2 ± 4.6 nM/mL/h in females and 1.4 ± 0.5 nM/mL/h in males (normal values > 3.0), whereas globotriaosylsphingosine was 2.3 ± 2.1 nM/L in females and 28.7 ± 3.5 nM/L in males (normal values < 2.0). Overall, cardiovascular, neurological, and audiological systems were the most involved, regardless of the variant detected. Patients with classic variants (10) showed typical multiorgan involvement and, in some cases, prevalent organ damage (cardiovascular, neurological, renal, and ocular). Those with late-onset variants (39) exhibited lower occurrence of multiorgan impairment, although some of them affected the cardiovascular and neurological systems more. In patients with lower enzymatic activity, the most frequent involvement was neurological, followed by peripheral vascular disease. (4) Conclusions: FD patients exhibited wide phenotypic variability, even at single-organ level, likely due to the individual genetic mutation, although other factors may contribute. Compared to the conventional management, a multidisciplinary approach, as that prompted at our Center, allows one to achieve early clinical detection and management.

A Human Stem Cell Model of Fabry Disease Implicates LIMP-2 Accumulation in Cardiomyocyte Pathology

Here, we have used patient-derived induced pluripotent stem cell (iPSC) and gene-editing technology to study the cardiac-related molecular and functional consequences of mutations in GLA causing the lysosomal storage disorder Fabry disease (FD), for which heart dysfunction is a major cause of mortality. Our in vitro model recapitulated clinical data with FD cardiomyocytes accumulating GL-3 and displaying an increased excitability, with altered electrophysiology and calcium handling. Quantitative proteomics enabled the identification of >5,500 proteins in the cardiomyocyte proteome and secretome, and revealed accumulation of the lysosomal protein LIMP-2 and secretion of cathepsin F and HSPA2/HSP70-2 in FD. Genetic correction reversed these changes. Overexpression of LIMP-2 directly induced the secretion of cathepsin F and HSPA2/HSP70-2, implying causative relationship, and led to massive vacuole accumulation. In summary, our study has revealed potential new cardiac biomarkers for FD, and provides valuable mechanistic insight into the earliest pathological events in FD cardiomyocytes.

Effective clearance of GL-3 in a human iPSC-derived cardiomyocyte model of Fabry disease

Fabry disease, a rare X-linked α-galactosidase A deficiency, causes progressive lysosomal accumulation of globotriaosylceramide (GL-3) in a variety of cell types. As the disease progresses, renal failure, left ventricular hypertrophy, and strokes may occur. Enzyme replacement therapy (ERT), with recombinant α-galactosidase A, is currently available for use to reduce GL-3 deposits. However, although it improves cardiac function and decreases left ventricular mass, GL-3 clearance upon ERT has been demonstrated in cardiac capillary endothelium but not in cardiomyocytes of patients. Relevant models are needed to understand the pathogenesis of cardiac disease and explore new therapeutic approaches. We generated induced pluripotent stem cells (iPSC) from Fabry patients and differentiated them into cardiomyocytes. In these cells, GL-3 accumulates in the lysosomes over time, resulting in phenotypic changes similar to those found in cardiac tissue from Fabry patients. Using this human in vitro model, we demonstrated that substrate reduction therapy via glucosylceramide synthase inhibition was able to prevent accumulation and to clear lysosomal GL-3 in cardiomyocytes. This new in vitro model recapitulates essential features of cardiomyocytes from patients with Fabry disease and therefore provides a useful and relevant tool for further investigations of new therapy.

Diagnosis and management of kidney involvement in Fabry disease

Interest in the diagnosis and treatment of Fabry disease has been greatly stimulated by the availability of Food and Drug Administration-approved, effective enzyme replacement therapy. This review will update the progress in this area since enzyme replacement therapy has become available. Fabry disease is often associated with proteinuric chronic kidney disease (CKD), and it appears that the treatment paradigms that have proven to be so effective in diabetes mellitus and other forms of proteinuric kidney disease are also effective in conjunction with enzyme replacement therapy for treating the kidney manifestations of Fabry disease. As such, Fabry disease represents an interesting example of progressive proteinuric kidney disease in which the usual blood pressure is lower than in other forms of CKD. This makes the use of effective antiproteinuric therapy challenging, especially considering the autonomic dysfunction that appears to be part of the disease. Comprehensive therapy for Fabry disease includes enzyme replacement therapy and all of the adjunctive therapies that are currently used to treat all forms of proteinuric CKD. It is anticipated that this approach will preserve kidney function and also benefit the cardiac and cerebrovascular systems in patients with Fabry disease.

Fabry disease: diagnosis and management, with emphasis on the renal manifestations

PURPOSE OF REVIEW

Interest in the diagnosis and treatment of Fabry disease has been greatly stimulated by the availability of Food and Drug Administration-approved, effective enzyme-replacement therapy. This review will update the progress in this area over the last 18 months that effective enzyme-replacement therapy has become available.

RECENT FINDINGS

Fabry disease is often associated with proteinuric chronic kidney disease, and it appears that the treatment paradigms that have proven to be so effective in diabetes mellitus and other forms of proteinuric renal disease are also effective, in conjunction with enzyme-replacement therapy for treating the renal manifestations of Fabry disease. As such, Fabry disease represents an interesting example of progressive proteinuric renal disease in which the usual blood pressure is lower than in other renal diseases. This makes the use of effective anti-proteinuric therapy challenging, especially considering the autonomic dysfunction that appears to be part of the disease. Recent advances are considered in this review, with emphasis on the role of kidney biopsy, effective dosing and maximal comprehensive therapy of Fabry disease.

SUMMARY

Maximal, comprehensive therapy for Fabry disease includes effective enzyme-replacement therapy and all of the adjunctive therapies that are currently used to treat all forms of proteinuric chronic kidney disease. It is anticipated that this approach will preserve kidney function and also benefit the cardiac and cerebrovascular systems in patients with Fabry disease.