Improvement of sympathetic skin responses under enzyme replacement therapy in Fabry disease

Aim To report the effect of enzyme replacement therapy (ERT) in sympathetic skin responses (SSR) of patients with Fabry disease. Patients and methods Seven male patients were included in an open-label protocol using agalsidase-alfa, continued at regular intervals. Five patients completed 24 months of ERT and two of them completed 18 months. Two main measurements were performed at baseline, as well as 1 and 2 years after ERT: (1) a standard neurological examination (NE), with a detailed evaluation of the sensory perception of light touch, pinprick, cold, hot, and vibratory stimuli; (2) the SSR amplitudes. Results Although there were no significant differences between NE in this time period, all patients reported general improvement in their subjective reports of acroparaesthesia and sweating. Before starting ERT, the SSR amplitudes were either too small (3/7 patients) or absent (4/7 patients): the average (range) amplitude of 122 mu V (0 through 492) was statistically smaller than that found in a control group, i.e. 1453.6 mu V (619.7-2754) (p < 0.0001, t-test). Mean +/- SD SSR amplitude increased to 1088 +/- 690 mu V in the second year of ERT, reaching the range found in a normal control group (p=0.004). Conclusion ERT improved SSR continuously in Fabry patients in 2 years of observation. Although the mechanism of the SSR improvement is unknown, this response to ERT can be clinically significant if it reflects a normalization in sweating.