Age at First Cardiac Symptoms in Fabry Disease: Association with a Chinese Hotspot Fabry Mutation (IVS4+919G>A), Classical Fabry Mutations, and Sex in a Taiwanese Population from the Fabry Outcome Survey (FOS).

This is a descriptive analysis of a cohort of 59 Taiwanese patients with Fabry disease and either classical Fabry or cardiac variant IVS4+919G>A (IVS4) mutations from a disease registry, the Fabry Outcome Survey (FOS; sponsored by Shire). Most of our classical Fabry patients were symptomatic and were identified upon seeking medical advice at our clinics, whereas most of our IVS4 patients attended our clinics after newborn screening identified this mutation in their grandsons. The objective was to determine differences in cardiac manifestations between patients with classical Fabry or IVS4 mutations by comparing age at onset of selected cardiac symptoms. Data were extracted in August 2013 and analyzed retrospectively. Fifty-nine Taiwanese patients (median age at extract 60.7 years [range 15.0-86.9]; n = 36 [61%] male) with proven IVS4 (n = 41 [69%]) or classical Fabry mutations (n = 18 [31%]) had available data on cardiac symptoms. Of 55 (93%) patients with reported left ventricular hypertrophy (LVH), mean [SD] age (years) at first symptom was lower in classical Fabry males (30.0 [15.1]; n = 4) than classical Fabry females (49.6 [8.9]; n = 11; p < 0.05), but not in IVS4 females (57.4 [13.7]; n = 10) compared with IVS4 males (55.9 [11.3]; n = 30). Mean age at first LVH diagnosis was significantly lower in classical Fabry males versus IVS4 males (p < 0.05). No significant difference in age at onset of arrhythmia or conductive abnormality, chest pain, or palpitations or cardiac syncope was found between the groups. The most noteworthy finding of this study is the lack of a significant gender sex difference in age at onset of cardiac symptoms in IVS4 patients.