CORRESPONDENCE: LETTER TO THE EDITOR
Reply
Lorenzo Monserrat, MD*,
Juan Ramón Gimeno-Blanes, MD,
Francisco Marín, MD,
Manuel Hermida-Prieto, PhD,
Antonio García-Honrubia, MD,
Inmaculada Pérez, BS,
Xusto Fernández, MD,
Gonzalo de la Morena, MD,
Eduardo Payá, MD,
Jordi Yagüe, PhD and
Jesús Egido, MD
* Cardiology Service, Complejo Hospitalario Universitario Juan Canalejo, As Xubias 84, A Coruna 15006, Spain (Email: lorenzo_monserrat{at}canalejo.org).
Dr. Linthorst and colleagues comment on an aknowledged limitation of our study (1) about the prevalence of Fabry disease in a cohort of 508 unrelated patients with hypertrophic cardiomyopathy. We state in our report that in female carriers plasma enzymatic activity might be within the normal range, and the screening could have a significant number of false negative results. For that reason we sequenced the alpha-galactosidase (GLA) gene in women with borderline activity (30% to 50%). Of course we could have missed the diagnosis in any female carrier with an activity >50% (we have such carriers in our own families). For this reason, we proposed in our discussion that sequencing of the GLA gene should be done in women with hypertrophic cardiomyopathy and even with normal or borderline activities had other clinical or family characteristics that could suggest the diagnosis of Fabry disease (renal disease, early cerebrovascular disease, angiokeratoma, corneal opacities, heat intolerance, hypoacusia, and so forth). However, we think that the number of female carriers with hypertrophic cardiomypathy secondary to Fabry disease with normal plasmatic GLA activity is probably very low. Moreover, we have to bear in mind that genetic variants in the GLA gene are not always disease-causing mutations. The editorial from Ackerman et al. (2) about our report discusses the cost-effectiveness of a universal screening of patients with hypertrophic cardiomyopathy by means of genotyping patients with low enzymatic activity. At present, universal genetic study of the GLA gene in patients with hypertrophic cardiomyopathy would be even less cost-effective.
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1. Monserrat L, Gimeno-Blanes JR, Marin F, et al. Prevalence of Fabry disease in a cohort of 508 unrelated patients with hypertrophic cardiomyopathy J Am Coll Cardiol 2007;50:2399-2403.[Abstract/Free Full Text]2. Ackerman MJ, Landstrom AP. Detection of subclinical Fabry disease in patients presenting with hypertrophic cardiomyopathy J Am Coll Cardiol 2007;50:2404-2405.[Free Full Text]
Related Article
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Enzyme Activity for Determination of Presence of Fabry Disease in Women Results in 40% False-Negative Results
- Gabor E. Linthorst, Ben J.H.M. Poorthuis, and Carla E.M. Hollak
J. Am. Coll. Cardiol. 2008 51: 2082.
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