Fabry cardiomyopathy presenting as hypertrophic phenotype with left ventricular outflow tract obstruction: a case series.

BACKGROUND: Fabry disease is a cardiomyopathy with multisystemic manifestations that is easily to be misdiagnosed as another type of cardiomyopathy. Fabry cardiomyopathy may present with left ventricular outflow tract obstruction (LVOTO), mimicking obstructive hypertrophic cardiomyopathy (oHCM). We present three cases of genetically confirmed Fabry disease that were initially misdiagnosed as oHCM, highlighting the importance of early recognition and tailored management. METHODS: We performed Fabry disease screening on patients diagnosed with oHCM and ultimately identified three individuals who have received oHCM-specific treatments including mavacamten and alcohol septal ablation. RESULTS: Three patients (2 females, 1 male; aged 48-66 years) who were initially diagnosed with and managed for oHCM based on septal hypertrophy and elevated left ventricular outflow tract gradients (LVOTG), was found to have GLA gene mutations. Enzyme replacement therapy with agalsidase alfa in two patients was associated with stabilization or improvement in wall thickness and LVOTO. CONCLUSION: Fabry cardiomyopathy can present with a hypertrophic phenotype and significant LVOTO, and is often misdiagnosed as oHCM. This further underscores the importance of genetic testing in the etiological diagnosis of hypertrophic cardiomyopathies. Enzyme replacement therapy may ameliorate obstruction, while mavacamten and septal reduction therapies require caution without definitive genotype-phenotype correlation.