A Natural History Study to Assess the Clinical Outcomes of Patients With Complement Factor I Deficiency-Mediated Disease

Inclusion Criteria: 1. Male or female, age 6 months or older 2. Affirmation of participant's informed consent or legally authorized representative (LAR)'s willingness to provide informed consent with signature confirmation before any study-related activities. (Study-related activities are any procedures that would not have been performed during normal clinical management of the participant.) The participant (if a minor) must also be willing to give written informed assent (if able) if the minor is within the age groups 7 to 11 years old and 12 to 17 years old. 3. Confirmed CFI deficiency during the screening study, CFI-001, with a disease that is associated with an absence or deficiency in CFI 4. Stated willingness of the participant to comply with all study procedures (including multiple blood draws) and availability for the duration of the study 5. Stated willingness of the participant (or LAR) to allow access to his/her medical records with the purpose of assessing disease status and progression during his/her participation in the study Exclusion Criteria: 1. Participation in an interventional clinical study within the previous 30 days prior to screening or within ≤5 half-lives of the investigational drug, whichever is longer 2. Having a major concurrent non-CFI-related disease that prevents the assessment of the natural course of the CFI deficiency disease 3. Having a medical, psychosocial, or familial issues that might prevent full participation and cooperation with the procedures and requirements of the clinical study as determined by the potential participant/guardian and physician investigator