Atypical Hemolytic-Uremic Syndrome (aHUS) Registry

Inclusion Criteria:

* Male or female patients of any age, including minors, who have been diagnosed with aHUS
* Patients with or without an identified complement pathogenic variant or anti-complement factor antibody
* Able to give written informed consent. Patient or patient's parent/legal guardian must be willing and able to given written informed consent and the patient (if minor) must be willing to give written informed assent \[if applicable as determined by the central Institutional Review Boards/Independent Ethics Committees (IRB/IEC)\].
* ADAMTS13 \> 5%, if performed.

Exclusion Criteria:

* Hemolytic Uremic Syndrome (HUS) only due to Shiga Toxin producing Escherichia coli (STEC).
* Unable to give written informed consent. Patient or patient's parent/legal guardian unable to give written informed consent. Patient (if minor) unable to give written informed assent (if applicable as determined by the central Institutional Review Boards/Independent Ethics Committees \[IRB/IEC\]).