Formeck C, et al. - Researchers focused on extra-renal manifestations of atypical hemolytic uremic syndrome (aHUS). They found that many organ systems, including the peripheral and central nervous, gastrointestinal, cardiovascular, integumentary, pulmonary, as well as the eye, can be affected besides kidney in aHUS, as far as extra-renal manifestations are concerned. The occurrence of some of these extra-renal manifestations is seen in the acute phase of the disease, while unopposed complement activation can result in some of these manifestations in the long-term. Nearly 20% of patients with aHUS exhibit extra-renal symptoms. The range of the incidence of specific organ system complications was from a few case reports to 50% of described patients. In aHUS cases, it is important to perform careful monitoring for extra-renal involvement because the risk of high morbidity and mortality related to aHUS may be attenuated by prompt evaluation and management.