Remaining patients were offered a similar observational study (Alexion M11-001) to allow for robust, high quality data collection in a larger, single database

There is growing but limited information on the long term clinical status of aHUS patients who have previously received or are continuing to receive treatment with eculizumab. This study is designed to collect clinical data that will provide insight into the long-term outcomes of patients with aHUS.

Inclusion Criteria:

• aHUS patients who participated in any one of the aHUS-eculizumab clinical studies.
• aHUS patients or legal representative who are able and willing to given written informed consent for their study information to be collected and retained in a database.

Exclusion Criteria:

• Not applicable.

Male and female aHUS, including minors, who previously participated in eculizumab clinical trials.