Abstract 19678: Anderson-Fabry Disease in Patients With Hypertrophic Cardiomiopathy: Differential Diagnosis

Introduction: Anderson-Fabry disease (AFD) is a rare pathology which is inherited by the X chromosome. It is caused by mutations of the gene that encodes the α-galactosidase A lysosomal enzyme. It is associated with multisystemic disorders, including renal, cutaneous, neurological and cardiac manifestations. The isolated cardiac form is even rarer, with few reports in the literature. The differential diagnosis with Hypertrophic Cardiomyopathy (HC) is hard, although it is essential because AFD has a specific treatment. Hypothesis: We assessed the prevalence of AFD and the factors related to its diagnosis in patients initially diagnosed with HC. Methods: We randomly selected a cohort of 106 patients with an initial diagnosis of HC, and applied genetic and/or enzymatic testing for AFD, during the period of January 2013 to January 2016. All patients had only cardiac manifestations. We assigned patients into 2 groups (positive Vs. negative test for AFD) and evaluated them clinically, demographically, echocardiographically and electrocardiographically. Univariate analyzes were performed using the chi-square and Fisher tests. Results: Three patients presented positive genetic and/or enzymatic testing for AFD (2.8%). The presence of three or more risk factors for sudden death (SD) was a significant factor for the diagnosis of AFD (p = 0.001) as well as the indication of Implantable Cardioverter Defibrillator (ICD) (p = 0.017), right anterior fascicular block (RAFB) in the electrocardiogram (p = 0.047), septal thickness > 25mm (p=0.04) and left ventricular mass (LVM) > 400g (p =0.022). The diagnosis of AFD was not correlated statistically to gender, race, thickness of the LV posterior wall, but there was a trend for association with left atrial enlargement (p = 0.055) and SD in relatives under 40 years old (p = 0.074). Conclusions: The differential diagnosis of HC and AFD can be done by considering factors such as: septal thickness > 25 mm, the presence of three or more risk factors for SD, LVM > 400 g, indication of ICD and RAFB in the electrocardiogram, which in this study were statistically associated with the diagnosis of AFD. The prevalence of AFD in a random cohort of patients initially diagnosed with MH was similar to that found in other studies in the literature (2.8%).