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Complement Genetic Feature

Complement System
Complement System Overview
- What is Complement System
- How Does Complement System Work
- Complement Protein Fragment Nomenclature
- Complement System Component / Protein Regulator and Receptor
- Complement Component / Protein of Complement System
- Complement Regulator of Complement System: RCA/CCP family
- Complement Regulator of Complement System: Others
- Complement Receptors of Complement System
Complement Genetic Feature
- Regulator of complement activation / RCA Gene Cluster
- Complement MAC Gene Cluster
- Complement MHC Class III Gene Cluster
Complement Activation Pathways
- Complement Activation Definition
- Complement Activation Classical Pathway
- Complement Activation Alternative Pathway
- Complement Activation Lectin Pathway
- Serine Proteases of Complement Activation Pathway
Complement System Role
- Complement System and Direct Interactions
- Complement System Function in Immune System
- Complement-Dependent Cytotoxicity/CDC
- Therapeutic Target of Complement System
- Complement System and Toll-like Receptors / TLRs
- Complement System and Coagulation
- Complement Cascade and Inhibitors
- Complement Evasion of Pathogens
- Complement System and Antimicrobial Peptides/AMPs
Complement System and Diseases
- Complement System and Cancer
- Complement System and Rheumatic Diseases
- Complement Receptor 1 / CR1 and Alzheimer's Disease / AD
- Complement System and Autoimmune Diseases
- Complement System and Age-Related Macular Degeneration/AMD
- Complement System and Schizophrenia
Complement System Deficiency Diseases
- Classical Pathway Deficiency
- Alternative Pathway Deficiency
- Complement Receptor Deficiency
- Mannose-Binding Lectin / MBL Pathway Deficiency
- Membrane Attack Complex/MAC Deficiency
- Total Complement Activity / CH50 / CH100
Complement System Structure
- Complement Membrane Attack Complex/MAC
- Complement Component / Protein Structure
- Complement Regulator Structure
- Complement Receptor Structure
- Collectins and Ficolins: Humoral Lectins of the Innate Immune System
Complement System Effector Functions
- Complement Mediated Opsonization
- Complement Mediated Cell Lysis
- Complement Mediated Phagocytosis
- Complement Mediated Inflammation
- Complement Mediated Chemotaxis
- Complement Mediated Antibody Formation
Anti-Complement Antibody Products

Complement Genetic Polymorphism

The complement system is an important part of non clonal or innate immunity that collaborates with acquired immunity to kill pathogens and to facilitate the clearance of immune complexes. The complement is made up of 20 distinct plasma proteins and 9 different membrane proteins. Three components, factor B, C2 and C4 (with 2 isotypes), are coded by polymorphic HLA-linked genes and are sometimes referred to as MHC class III antigens, inherited as compact units called complotypes. The C4 genes are the most polymorphic, including a common null allele (Q0) at both the C4A and C4B loci. Other polymorphic complement factors (not linked to HLA) are C3 (2 common alleles), C6 and C7 (closely linked, with 3 and 2 alleles, respectively). A certain degree of polymorphism has also been described for complement receptors and membrane control proteins. No differences in functional activity are usually detected among different alleles.

Human complement C3 exhibits genetic polymorphism that was first described by Weime and Demeulenaere and Alper and Propp in 1986. The genetic variants of the protein are inherited as autosomal codominant traits and are characterized using prolonged agarose gel electrophoresis of fresh serum. In this way, two common polymorphic forms have been found, designated C3F and C3S. The C3S allele is most common in all races in humans. The C3F allele is relatively frequent in Caucasoids, less common in America Negroes, and extremely rare in Orientals. More than 20 rare allotypes have been characterized by variations in their relative electrophoretic mobilities.

Complement Deficiency Diseases Complement System Structure Complement Activation Pathways

Complement Genetic Feature References

1. Botto M, et al. (1990). Molecular basis of polymorphisms of human complement component C3. The Journal of experimental medicine, 172(4), 1011-1017.
2. Brai M, et al. (1993). Polymorphism of the complement components in human pathology. Annali italiani di medicina interna: organo ufficiale della Societa italiana di medicina interna, 9(3), 167-172.