FabryScan: a screening tool for early detection of Fabry disease

Fabry disease, an X-linked lipid storage disorder, is associated early morbidity and mortality. Since enzyme replacement therapy is available, accurate detection of unrecognized cases is important. Characteristic early symptoms are recurrent episodes of burning and lancinating pain in the distal extremities associated with small fiber neuropathy. The aim was to develop and validate an easy diagnostic questionnaire in combination with three simple bedside tests, the "FabryScan", for the detection of Fabry disease in patients with chronic extremity pain. Questions related to relevant clinical characteristics of Fabry disease (mainly related to pain) were compiled by Fabry specialists and pain experts. Furthermore, three bedside tests assessing sensory small and large fiber function were established. The provisional version was tested in a prospective multicenter trial of 138 patients with chronic extremity pain due to Fabry disease (n = 55), painful polyneuropathy (n = 40), and rheumatoid arthritis (n = 43). Identification of the most discriminant combinations of items for Fabry disease and their calculation of sensitivity and specificity were based on multivariate analyses. We retained only 10 questions and three bedside tests for the final version of the FabryScan. A cut-off score of 12/33 (corresponding to the number of positive points) resulted in a high proportion of correctly identified patients (76 %) with a sensitivity of 88 % and a specificity of 87 %. The FabryScan is a combination of a brief and simple questionnaire with three simple bedside tests with good discriminative value for the identification of Fabry patients in patients with chronic extremity pain.