Clinical Research Directory

Inclusion Criteria: 1. Children and adults under eculizumab treatment for aHUS (initial episode or relapse) defined by at least two of the following: thrombocytopenia (platelet count \< 150 G/L), mechanical hemolytical anaemia (Hb \< 10 g:dl, LDH \> upper limit of normal, undetectable haptoglobin, presence of schizocytes on blood smear), acute kidney injury (serum creatinine and/or proteinuria/creatininuria \> upper limit of normal for age or an increase \> 15% compared to baseline levels ) 2. Patients not requiring dialysis. 3. Adults: HUS remission and normal or stabilized renal function under eculizumab treatment since at least 6 months (3 months in patients with MCP mutations) 4. Children: age \> 3 years at eculizumab withdrawal; HUS remission and normal renal function under eculizumab treatment since at least 3 months in children with isolated MCP mutation, at least 6 months in children with complement mutation other than MCP. Exclusion Criteria: 1. Patients on dialysis. 2. Women treated with eculizumab starting or planning a pregnancy. Pregnancy including the post-partum period is high-risk periods for the occurrence of aHUS. 3. Patients who did not give informed consent. 4. Patients under protection of a judicial authority Patients can be enrolled in the study within ten weeks after Eculizumab stop.