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 hematuria, hypertension, and 
bruises over the entire body were noted in a 5 day-old newborn. Investigations 
revealed hemolytic 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 
uncontrolled 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 homozygous 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.