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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.

Fabry disease (FD) is a lysosomal storage disorder caused by mutations of the GLA gene that lead to a deficiency of the enzymatic activity of α-galactosidase A. Available therapies for FD include enzyme replacement therapy (ERT) (agalsidase alfa and agalsidase beta) and the chaperone migalastat. Despite the large body of literature published about ERT over the years, many issues remain unresolved, such as the optimal dose, the best timing to start therapy, and the clinical impact of anti-drug antibodies. Migalastat was recently approved for FD patients with amenable GLA mutations; however, recent studies have raised concerns that "in vitro" amenability may not always reflect "in vivo" amenability, and some findings on real-life studies have contrasted with the results of the pivotal clinical trials. Moreover, both FD specific therapies present limitations, and the attempt to correct the enzymatic deficiency, either by enzyme exogenous administration or enzyme stabilization with a chaperone, has not shown to be able to fully revert FD pathology and clinical manifestations. Therefore, several new therapies are under research, including new forms of ERT, substrate reduction therapy, mRNA therapy, and gene therapy. In this review, we provide an overview of the state-of-the-art on the currently approved and emerging new therapies for adult patients with FD.

Background: Knowledge on clinical profiles of late-onset phenotypes of Fabry disease (FD) is essential to better define their natural history. Our study aims to demonstrate a founder effect of FD due to the GLA gene mutation c.337T>C (p.F113L) in the Portuguese region of Guimarães; and to characterize the clinical profile of this late-onset phenotype in a large cohort of genetically related adult patients, living in the same region., Methods and Results: FD screening was performed in 150 adult patients with hypertrophic cardiomyopathy (HCM) and found 25 Fabry patients (16.6%). The p.F113L mutation was found in 21 of them, leading to a genealogy study and haplotype analysis of the p.F113L patients. Genealogy research revealed a 12-generation family tree with a common ancestor to p.F113L patients, suggesting a founder effect that was supported by haplotype findings. Pedigree analysis was performed and 120 consecutive p.F113L patients underwent a predefined diagnostic evaluation of FD multiorgan involvement. This late-onset phenotype was characterized by common and/or potentially severe cardiac manifestations (left ventricular hypertrophy 40.8%, atrial fibrillation 5%, non-sustained ventricular tachycardia 12.5%, atrioventricular block 18.3%, bifascicular block 13.4%). Extracardiac manifestations included albuminuria>30 mg/24 h 36.1%, chronic kidney disease≥G3 7.6%, brain white matter lesions 54.4%, stroke 3.3%, sensorineural deafness 44.5%, cornea verticillata 13.9%. Plasma lyso-GB3 was undetectable in females, regardless of clinical manifestations., Conclusion: A founder effect of FD due to p.F113L mutation was documented by genealogy and genetics in a Portuguese region. In this late-onset phenotype, although cardiac manifestations carry the highest prognostic impact, extracardiac involvement is common., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Sporadic Parkinson's disease (PD) patients have lower α-galactosidase A (α-GAL A) enzymatic activity and Fabry disease (FD) patients potentially carry an increased risk of PD., Objective: Determination of PD prevalence in FD and clinical, biochemical and vascular neuroimaging description of FD pedigrees with concomitant PD., Methods: Clinical screening for PD in 229 FD patients belonging to 31 families, harbouring GLA gene mutation p.F113L, and subsequent pedigree analysis. Gender-stratified comparison of FD+/PD+ patients with their family members with FD but without PD (FD+/PD-) regarding Mainz scores, plasma & leukocytes α-GAL A enzymatic activity, urinary Gb3 and plasma Lyso-Gb3, vascular brain neuroimaging., Results: Prevalence of PD in FD was 1.3% (3/229) (3% in patients aged ≥50 years). Three FD patients, one female (73 years old) (P1) and two males (60 and 65 years old) (P2 and P3), three different pedigrees, presented akinetic-rigid PD, with weak response to levodopa (16% - 36%), and dopaminergic deficiency on 18F-DOPA PET. No pathogenic mutations were found in a PD gene panel. FD+/PD+ patients had worse clinical severity of FD (above upper 75% IQR in Mainz scores), and cortico-subcortical white matter/small vessel lesions. P3 patient was under enzyme therapy, started 1 year before PD diagnosis. P2-P3 patients had higher leucocyte α-GAL A activity (2,2-3 vs.1,0 (median)(nmol/h/mg))., Conclusion: We have shown a high prevalence of PD in a late-onset phenotype of FD, presenting high cerebrovascular burden and weak response to levodopa. Further studies will untangle how much of this PD phenotype is due to Gb3 deposition versus cerebrovascular lesions in the nigro-striatal network.

The authors report the case of a classic phenotype of Fabry disease in a 60-year-old male patient presenting with left ventricular hypertrophy and stroke. Genetic analysis revealed 2 GLA-gene variants, i.e., p.R356Q and p.G360R. This clinical case highlights that the finding of 2 or more GLA gene variants in a Fabry patient should lead to a careful evaluation in order to determine their exact role in the condition. This case also provides the first clinical evidence that the p.G360R mutation is pathogenic and responsible for a classic phenotype of Fabry disease. The clinical improvement following the initiation of enzyme replacement therapy reinforces the importance of Fabry disease awareness and diagnosis in patients exhibiting red flags, such as left ventricular hypertrophy and stroke., (© 2019 S. Karger AG, Basel.)

We report on the clinical, biochemical, and genetic findings of a large family with the classical phenotype of Fabry disease due to the novel nonsense mutation c.607G>T (p.E203X) of the GLA gene, which occurs in the active site of the α-galactosidase A enzyme. This report highlights that (i) Fabry disease diagnosis should be considered in all cases of unexplained left ventricular hypertrophy (LVH), even in its milder forms; (ii) a complete evaluation of patients with unexplained LVH is important to find diagnostic red flags of treatable causes of LVH, such as Fabry disease; (iii) cascade family screening is paramount to the earlier diagnosis and treatment of other affected family members; and (iv) the Fabry disease phenotype is highly variable in heterozygote females, even within the same family., (© 2017 S. Karger AG, Basel.)