Diagnosis and Screening of Patients with Fabry Disease

Abstract

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by absence or deficient activity of α-galactosidase A (α-Gal A) due to mutations in the α-galactosidase A gene (GLA), leading to progressive accumulation of globotriaosylceramide (Gb3) in tissues and organs including heart, kidney, the eyes, vascular endothelium, the nervous system and the skin. Cardiac involvement is leading to fatal complications and reduced life expectancy. FD is treatable with disease-specific treatment (enzyme replacement therapy (ERT) or with chaperone therapy). Therefore, the early diagnosis of FD is crucial for reducing the morbidity and mortality. Screening of high-risk populations (eg, patients with unexplained left ventricular hypertrophy (LVH), young patients with unexplained stroke, and patients with unexplained renal failure proteinuria or microalbuminuria) yields good results. The diagnostic algorithm is gender-specific. Initially, the measurement of α-Gal A activity is recommended in males, and optionally in females. In males with non-diagnostic residual activity (5-10%) activity, genetic testing is afterwards done for confirming the diagnosis. In fact, diagnosis of FD is not possible without genetic testing for both males and females. Globotriaosysphingosine (lyso-Gb3) for identification of atypical FD variants and high- sensitive troponin T (hsTNT) for identification of cardiac involvement are also important diagnostic biomarkers. The aim of this review was to provide an update on diagnosis and screening of patients with FD.

Keywords: algorithm; genetics; heart failure; hypertrophic cardiomyopathy; metabolic disease; proteinuria.

Figure 1

Updated diagnostic algorithm for FD. Adapted with permission from van der Tol L, Smid BE, Poorthuis BJ, et al. A systematic review on screening for Fabry disease: prevalence of individuals with genetic variants of unknown significance. J Med Genet. 2014;51:1–9. Copyright © 2014, BMJ Publishing Group Ltd. Adapted with permission from Yogasundaram H, Kim D, Oudit O, Thompson RB, Weidemann F, Oudit GY. Clinical Features, Diagnosis, and Management of Patients With Anderson-Fabry Cardiomyopathy. Can J Cardiol. 2017;33:883–897. © 2017 Canadian Cardiovascular Society. Adapted with permission from Putko BN, Wen K, Thompson RB, et al. Anderson-Fabry cardiomyopathy: prevalence, pathophysiology, diagnosis and treatment. Heart Fail Rev. 2015;20:179–191. Copyright © 2014, Springer Nature. Adapted with permission from Laney DA, Bennett RL, Clarke V, et al. Fabry disease practice guidelines: recommendations of the National Society of Genetic Counselors. J Genet Couns. 2013;22:555–564. © 2013 National Society of Genetic Counselors, Inc. Data from Niemann et al  and Putko et al. α-Galactosidase A (α-Gal A), α-galactosidase A gene (GLA gene), globotriaosysphingosine (Lyso-Gb3), left ventricular (LV). *Punch biopsy, taken from proximal (thigh: 15 cm above the patella) and distal (leg: 10 cm above the lateral malleolus) hairy skin sites or from other lesions to evaluate Gb3 deposits, and for other histopathological evaluations.