Table 2.
Genes associated with the Alternative Complement Pathway
| Gene | Name | Ensemble cytogenetic band | Case-Control Assoc with AMD | Within reported region of AMD linkage | Associated with Other MD, other potential roles |
|---|---|---|---|---|---|
| Alternative Complement Pathway Components | |||||
| C1QA | Complement component 1, q subcomponent, A chain | 1p36.12 | - | - | C1q associates with C1r and C1s to form C1. Deficiency of C1q has been associated with lupus erythematosus and glomerulonephritis. |
| C1QB | Complement component 1, q subcomponent, B chain | 1p36.12 | - | - | C1q associates with the proenzymes C1r and C1s to yield C1 |
| C1QC | Complement component 1, q subcomponent, C chain | 1p36.12 | - | - | C1q associates with the proenzymes C1r and C1s to yield C1 |
| C1QBP | Complement component 1, q subcomponent binding protein | 17p13.2 | - | - | C1q associates with the proenzymes C1r and C1s to yield C1. Also is p32 subunit of pre-mRNA splicing factor SF2, as well as a hyaluronic acid-binding protein |
| C1R | Complement component 1, r subcomponent | 12p13.31 | - | - | a serine protease that combines with C1q and C1s to form C1, |
| C1S | Complement component 1 subcomponent s | 12p13.31 | - | - | a serine protease, which is a major constituent of the human complement subcomponent C1. |
| C2 | Complement component 2’ C3/C5 convertase | 6p21.33 | + | + | Also a major histocompatibility complex class-III protein |
| C3 | Complement component 3 | 19p13.3 | + | + | C3 plays a central role in the activation of the complement system.after cleavage by C3 convertase |
| C5 | Complement component 5 | 9q33.2 | - | + | C5 is activated by C5 convertase to initiate the assembly of the late complement components, C5-C9, into the membrane attack complex. |
| C6 | Complement component 6 | 5p13.1 | - | - | Constituent of the membrane attack complex (MAC) |
| C7 | Complement component 7 | 5p13.1 | + | + | The protein participates in the formation of Membrane Attack Complex (MAC). |
| C8A | Complement component 8 subunit alpha | 1p32.2 | - | - | Alpha subunit of C8. C8 is part of membrane attack complex (MAC) |
| C8B | Complement component 8 subunit beta | 1p32.2 | - | - | Beta subunit of C8. C8 is part of membrane attack complex (MAC) |
| C8G | Complement component 8 subunit gamma | 9q34.3 | - | + | Gamma subunit of C8. C8 is part of membrane attack complex (MAC) |
| C9 | Complement component 9 | 5p13.1 | - | + | C9 is the pore-forming subunit of the membrane attack complex (MAC) |
| Complement Regulatory Factors | |||||
| CFH | Complement factor H | 1q31.3 | + | + | Hemolytic-uremic syndrome |
| CFHR1 | Complement factor H-related 1 | 1q31.3 | + | + | Might be involved in complement regulation. Binds lipoproteins and may play a role in lipid metabolism |
| CFHR2 | Complement factor H-related 2 | 1q31.3 | + | + | Might be involved in complement regulation. Binds lipoproteins and may play a role in lipid metabolism |
| CFHR3 | Complement factor H-related | 1q31.3 | + | + | Active in complement regulation |
| CFHR4 | Complement factor H-related 4 | 1q31.3 | + | + | Binds lipoproteins and may play a role in lipid metabolism |
| CFHR5 | Complement factor H-related 5 | 1q31.3 | + | + | Active in complement regulation |
| CFB | Complement factor B | 6p21.33 | + | + | Factor B is cleaved by factor D into 2 fragments: Ba and Bb, a serine protease that associates with C3b |
| CFP | Complement factor properdin | Xp11.23 | - | - | Plasma glycoprotein that positively regulates the alternative complement pathway |
| CFI | Complement factor I | 4q25 | + | (+) | Cleaves the alpha-chains of C4b and C3b in the presence of C4-binding protein and factor H respectively. Associated with atypical hemolytic uremic syndrome glomerulonephritis. |
| SERPING1 | Serpin peptidase inhibitor, clade G (C1 inhibitor), member 1 | 11q12.1 | +/- | + | The protein inhibits activated C1r and C1s and regulates complement activation. Assoc. with hereditary angioneurotic edema |