BRIEF REPORT Neonatal onset atypical hemolytic uremic syndrome successfully treated with eculizumab Nesrin Besbas & Bora Gulhan & Diana Karpman & Rezan Topaloglu & Ali Duzova & Emine Korkmaz & Fatih Ozaltin Received: 3 July 2012 / Revised: 2 August 2012 / Accepted: 7 August 2012 / Published online: 6 September 2012 # IPNA 2012 Abstract Background Atypical hemolytic uremic syndrome (aHUS) is characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and renal impairment. Neonatal cases are extremely uncommon. Plasma therapy is the first choice therapy in patients with aHUS based on the belief of an underlying complement dysregulation. Alternatively, eculizumab, which targets complement 5, is used to block complement activation. Case-diagnosis/treatment Sudden onset macroscopic hema- turia, hypertension, and bruises over the entire body were noted in a 5 day-old newborn. Investigations revealed he- molytic anemia, thrombocytopenia, renal impairment, and a low serum C3, leading to the diagnosis of aHUS. Fresh frozen plasma (FFP) infusions and peritoneal dialysis for acute kidney injury were initiated. This approach yielded full renal and hematological remission. The patient was discharged with FFP infusions, but subsequently developed three life-threatening disease recurrences at 1, 3, and 6 months of age. The last relapse presented with uncon- trolled hypertension and impaired renal function while the patient was receiving FFP infusions. After the first dose of eculizumab, his renal and hematological parameters returned to normal and his blood pressure normalized. Genetic screening of the CFH gene revealed a novel homo- zygous p. Tyr1177Cys mutation. Conclusion Eculizumab can be considered as an alternative to plasma therapy in the treatment of specific patients with aHUS, even in infants. Keywords Atypical hemolytic uremic syndrome . Complement factor H mutation . Eculizumab . Newborn Introduction Atypical hemolytic uremic syndrome (HUS) is a rare dis- ease and is characterized by the triad of microangiopathic hemolytic anemia [hemoglobin (Hb) <10 g/dL] with frag- mented erythrocytes (schistocytes), thrombocytopenia (<150×10 9 /L), and renal impairment (serum creatinine > upper limit of normal age) [1, 2]. Atypical HUS (aHUS) accounts for 5–10 % of all HUS cases and often results from complement dysregulation and mutations in genes encoding complement regulatory proteins or complement factors [2, 3]. These include mutations in genes encoding complement factor H (CFH), complement factor I (CFI), membrane cofactor protein (MCP), and factor B and C3, which are detected in more than 50 % of patients with aHUS. In certain patients antibodies against factor H may contribute to the disease, and these have been associated with deletions in factor H-related proteins 1 and 3 [4]. Mutations in the thrombomodulin gene have also recently been uncovered [5]. Inborn errors of cobalamin metabolism can also cause aHUS [6]. Cobalamin disorders form a large group of dis- eases that can appear from the first days or weeks of life to significantly later stages in childhood. There is a wide spectrum of clinical signs and symptoms related to cobala- min disorders, from neurological or psychiatric problems to multisystem disease with a more complex clinical picture. Among these, aHUS is the least common and has been N. Besbas : B. Gulhan : R. Topaloglu : A. Duzova : F. Ozaltin (*) Department of Pediatric Nephrology, Hacettepe University Faculty of Medicine, 06100 Sihhiye, Ankara, Turkey e-mail: fozaltin@hacettepe.edu.tr D. Karpman Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden E. Korkmaz : F. Ozaltin Nephrogenetics Laboratory, Department of Pediatric Nephrology, Hacettepe University Faculty of Medicine, Ankara, Turkey Pediatr Nephrol (2013) 28:155–158 DOI 10.1007/s00467-012-2296-4