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 a-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 (activitiy 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.