Atypical hemolytic-uremic syndrome (aHUS) is a rare, potentially lethal systemic disorder, capable of affecting both adults and children, causing thrombotic microangiopathy (TMA) that leads to the formation of thrombus within small blood vessels with multiple organ failure. The pathogenesis of the aHUS is part of a sort of chronic and uncontrolled activation of the complement system by genetic mutation of some proteins usually responsible for its self-regulation. Today, the rapid diagnosis of the disease and the timely start of treatment with eculizumab, improve outcomes of renal failure, stroke and heart attack. Fabry disease is a rare tesaurismosis, X linked, due to the deficiency of the lysosomal enzyme alpha-galactosidase A, necessary for the physiological catabolism of glycosphingolipids. Multisystem clinical manifestations lead to a serious degenerative pathology. The diagnostic suspicion based on anamnesis and careful research of the symptoms and then confirmed by the enzymatic dosage of alpha galactosidase or by molecular analysis, allows the early treatment of the patient with enzyme replacement therapy, guaranteeing the resolution and/or slowing down the evolution of the disease, especially in the brain, heart and kidneys. In this report, we describe the clinical case of a patient who is a carrier of both rare diseases. Everything regarding the case, you can find here.