Absence of systolic anterior motion in fabry disease: implications for mitral regurgitation pathophysiology

Abstract Introduction Fabry disease (FD) is an X-linked lysosomal storage disorder caused by mutations in the GLA gene, resulting in α-galactosidase deficiency. Cardiac involvement is characterized by myocardial and papillary muscle hypertrophy, thickening of the subvalvular apparatus, and increased rigidity of the mitral valve. Mitral regurgitation (MR) is more prevalent in patients with FD compared to the general population (1). Purpose In patients with Fabry disease-related cardiac involvement, MR and left ventricular outflow tract obstruction (LVOTO) are more frequently observed. Considering the structural similarities to hypertrophic cardiomyopathy (HCM), where systolic anterior motion (SAM) of the mitral leaflet occurs in 25–50% of cases (2,3,4,5), we hypothesized that SAM might similarly contribute to MR in a subset of FD patients. We know that any distance