Alt. symbols: CPAMD1 | ARMD9 | C3a | C3b

Approved name: complement C3
Alt. names: complement component 3 | C3a anaphylatoxin, complement component C3a, complement component C3b, prepro-C3

Location: 19p13.3: 6677704 - 6730562 (-)
Gene type: protein_coding, 28 transcripts.

Scores: LoFtool: 0.335000 | pLI: 0.99959015 | LOEUF: 0.305

HGNC: 1318

NCBI: 718, RefSeq: NG_009557.1

Ensembl: ENSG00000125730.18

LRG_27 | Status: public

OMIM: 120700

Expression | ProteinAtlas

The C3 gene encodes the complement component 3 (or C3). This protein plays a key role in the complement system. The complement system is a group of proteins that work together to destroy pathogens, trigger inflammation, and remove debris from cells and tissues. The C3 protein is essential for activating the complement system. The presence of foreign invaders triggers the C3 protein to be cleaved into two smaller pieces. One of these pieces, called C3b, interacts with several other proteins on the surface of cells to trigger the complement systemís response. This process must be carefully regulated so the complement system targets only unwanted materials and does not damage the bodyís healthy cells. Two major forms (or allotypes) of the C3 protein, known as C3S and C3F have been identified. In the general population, C3S is more common than C3F. The two allotypes differ by a single amino acid, although it is unclear whether they function differently.

Mutations in C3 have been associated with various conditions, including C3 immune deficiency, C3 glorumelopathy, atypical hemolytic-uremic syndrome (aHUS) and age-related macular degeneration [MIM:611378]. At least 17 loss-of-function mutations have been described to cause C3 immune deficiency [MIM:613779], a rare autosomal recessive condition characterized by recurrent bacterial infections beginning in childhood. At least one gain-of-function mutation in C3 has been associated with a rare form of kidney disease called C3 glomerulopathy. This disorder damages the kidneys and can lead to end-stage renal disease (ESRD), a life-threatening condition that prevents the kidneys from filtering fluids and waste products from the body effectively. This mutation overactivates the complement system, which then causes damage to the glomeruli in the kidneys. Other variants in C3 do not cause C3 glomerulopathy directly, but appear to increase the likelihood of developing the disorder. In particular, the C3F allotype is seen more frequently in people with this condition than in the general population (C3S allotype). Monoallelic -mostly hypomorphic missense - variants in C3 have also been associated with increased susceptibility to the development of aHUS [MIM:612925]. [Load More]