Prevalence of fabry disease in a cohort of 508 unrelated patients with hypertrophic cardiomyopathy.

OBJECTIVES: We aimed to study the prevalence of Fabry disease (FD) in patients with hypertrophic cardiomyopathy (HCM). BACKGROUND: There are limited and controversial data about the prevalence of FD in patients with HCM. METHODS: We screened the plasma alpha-galactosidase A activity from 508 unrelated patients with HCM (328 men, 180 women, ages 58 +/- 16 years). Patients with low activity (0% to 30% of the normal control in men, and 0% to 50% in women) underwent genetic study of the GLA gene. RESULTS: We found low plasma activity in 15 patients (3%). Three men had GLA mutations (0.9%): S238N (novel) in 2 and E358del (described) in 1. Two women had described mutations (1.1%): L89P and A143T. Three unrelated men had the D313Y variant previously associated with enzyme pseudo-deficiency. Two women had polymorphisms that did not segregate with the disease in their families. Five women (activity 39% to 47%) had no sequence variants. The familial studies allowed the diagnosis of 14 carriers: 6 women without Fabry manifestations, 3 women with cardiomyopathy, 2 men with renal and cardiac disease, 1 man with microhematuria, 1 woman with first-degree atrioventricular block, and a 32-year-old woman with only renal disease. CONCLUSIONS: By means of a screening based on genotyping of patients with low plasma enzymatic activity, the prevalence of FD in our population of HCM is 1% (0.9% in men and 1.1% in women). This diagnosis is relevant, because it allows the identification of disease carriers that might benefit from enzyme replacement therapy.