Background Patients with Fabry disease (FD) show left ventricular hypertrophy (LVH) mimicking hypertrophic cardiomyopathy (HCM) of sarcomeric origin and might benefit, if detected early, from specific enzyme replacement therapy. The prevalence of FD in patients with LVH of 13 mm or greater, screened using the leucocyte alpha-galactosidase A (α-gal A) activity test, a technique that is difficult to apply routinely, ranged from 0% to 6%.
Objective To screen systematically for FD in patients with a diagnosis of HCM (LVH ≥15 mm) in primary cardiology practice, a validated, physician-friendly α-gal A assay was used on dried blood spots using a filter paper test.
Design and patients A cohort of 392 adults (278 men) followed for HCM were screened for FD. A standard blood test was used for confirmation in nine men in whom the α-gal A result was 40% or less.
Results Four men (1.5%; 1.8% of men ≥40 years vs 0% <40 years; all with α-gal A <30%), but no women, were diagnosed with FD. Index cases presented with diffuse but asymmetric LVH, with severe obstruction in one case and frequent high-grade atrioventricular conduction block necessitating a pacemaker in three cases. Family screening identified eight additional cases. Genotyping was performed successfully on DNA extracted from the filter papers.
Conclusion In male patients diagnosed as having HCM, pure FD cardiac variants are not exceptional and can be specifically identified using a simple filter-paper test. The sensitivity of this test is low in female patients.
- Cardiac variant
- cardiomyopathy hypertrophic
- Fabry disease
- filter-paper test
- hypertrophic cardiomyopathy
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Funding This study was supported by Genzyme SAS, Saint-Germain en Laye, France and the Centre de Référence de la maladie de Fabry et des maladies héréditaires du tissu conjonctif, CHU Raymond Poincaré, Garches, France.
Competing interests AAH and DPG have received research and consultancy funding from Genzyme SAS, Saint-Germain en Laye, France.
Patient consent Obtained.
Ethics approval This study was conducted with the approval of the ethical committee of Pitié Salpêtrière, Paris, no 11-06, favourable advice 20 March 2006, France.
Provenance and peer review Not commissioned; externally peer reviewed.
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