Anderson-Fabry's Disease: A Rare but Treatable Case of Fever of Unknown Origin

Anderson-Fabry's disease (AFD) is a rare, X-linked lysosomal storage disorder caused by the complete deficiency or attenuated activity of the enzyme α-galactosidase A, leading to progressive systemic intracellular accumulation of glycosphingolipids and subsequent cellular dysfunction, inflammation and fibrosis. Fever is a frequently misinterpreted symptom in the early stages of the disease, leading to diagnostic delay. We present the case of a 35-year-old man admitted to our Periodic Fever Research Centre for long-lasting recurrent episodes of fever of unknown origin. After extensive assessment, we diagnosed AFD associated with a novel GLA mutation. We started enzyme replacement therapy with clinical benefit and complete remission of fever. Learning points: Anderson-Fabry's Disease (AFD) is an inherited lysosomal storage disorder, in which progressive multi-organ glycosphingolipid accumulation leads to multi-systemic dysfunction. Diagnosis requires a high level of suspicion as the clinical presentation can be very heterogeneous.As fever is an early uncommon symptom causing diagnostic delay, it is important to consider AFD in the differential diagnosis of recurrent fevers, particularly when febrile episodes are not associated with an increase in acute phase reactants and when other signs or symptoms suggestive of AFD are present.Prognosis depends on an early diagnosis because promptly initiation of enzyme replacement therapy (ERT) can prevent the progression of organ damage. In our case fever disappeared after ERT initiation, a finding not previously reported to our knowledge. Therefore, fever remission could be an early marker of response to ERT.