The gene C3 encodes a crucial complement component. Loss-of-function mutations result in autosomal recessive C3 deficiency whereas gain-of-function mutations have been observed in atypical HUS. Some polymorphisms have been associated with age-related macula degeneration.
| Clinic | Method | Carrier testing |
| Turnaround | 5 days | |
| Specimen type | genomic DNA |
| Clinic | Method | Massive parallel sequencing |
| Turnaround | 25 days | |
| Specimen type | genomic DNA |
| Clinic | Method | Genomic sequencing of the entire coding region |
| Turnaround | 25 days | |
| Specimen type | genomic DNA |