Prevalence of Fabry disease in female patients with late-onset hypertrophic cardiomyopathy

Background-Fabry disease (FD) has been recognized as the cause of left ventricular hypertrophy in 6% of men with late-onset hypertrophic cardiomyopathy (HCM). Although FD is considered a recessive X-linked disorder, affected women are increasingly reported. The aim of our study was to determine the prevalence of FD in female patients with HCM. Methods and Results-Thirty-four consecutive women (mean age, 50+/-13.6 years) who received an ECG and echocardiographic diagnosis of HCM were submitted to an invasive cardiac study that included a biventricular endomyocardial biopsy. Tissue samples were analyzed for histology and electron microscopy. Peripheral blood activity of alpha-galactosidase (alpha-Gal) A was assessed in all patients. None of them had a family history of FD. Histology and electron microscopy showed in 4 patients (12%; mean age, 51.5+/-3.9 years) the presence of cell vacuoles characterized by the accumulation of glycolipid material organized in concentric lamellar structures, diagnostic for FD. In the remaining patients, histology was consistent with HCM. In all the female carriers, the heart was the only organ clinically involved in the disease, showing concentric hypertrophy in 2 patients, asymmetric hypertrophy in 1, and apical hypertrophy in 1. The alpha-Gal A enzymatic activity was 44+/-14% of control values. Genetic analysis showed the presence of alpha-Gal A gene mutation in all 4 cases. Conclusions-FD may account for up to 12% of females with late-onset HCM. Those heterozygous for FD with left ventricular hypertrophy are potential candidates for enzyme enhancement/replacement therapy.