Cfh is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
The CFH gene encodes complement factor H, a crucial soluble regulator of the alternative complement pathway. Factor H is the primary negative regulator of alternative pathway activation, preventing spontaneous C3b deposition on host cells and controlling complement amplification. The gene is located on chromosome 1q31.3 and encodes a protein of 1,121 amino acids [1].
Factor H is a member of the regulators of complement activation (RCA) protein family. It contains 20 short consensus repeat (SCR) domains, also known as complement control protein (CCP) modules. Each SCR domain is approximately 60 amino acids long and contains four conserved cysteine residues forming two disulfide bonds. The protein is synthesized primarily in the liver and circulates in plasma at concentrations of approximately 0.4-0.6 mg/mL [2].
Function
Factor H functions as the main soluble regulator of the alternative complement pathway:
Decay-Accelerating Activity: Factor H binds to C3b and accelerates the decay of the C3 convertase (C3bBb), displacing the Bb subunit [3]
Cofactor Activity: Factor H serves as a cofactor for factor I-mediated cleavage and inactivation of C3b
Host Recognition: Factor H recognizes host-specific markers including heparan sulfate, sialic acid, and glycosaminoglycans, distinguishing self from foreign surfaces
Alternative Pathway Control: By limiting alternative pathway amplification, factor H prevents excessive complement activation and tissue damage
Structural Organization
N-terminal domains (1-4): Mediate decay-accelerating and cofactor activity
Central domains (5-7): Bind C3b and C3d
C-terminal domains (18-20): Mediate host surface recognition and attachment
Disease Associations
Alzheimer's Disease
CFH has been implicated in [Alzheimer's disease](/diseases/alzheimers-disease) pathogenesis through multiple mechanisms:
Elevated CFH levels have been observed in AD brain tissue and cerebrospinal fluid [4]
CFH colocalizes with amyloid plaques in AD brain
The Y402H polymorphism (rs1061170) has been associated with altered AD risk in some populations
CFH may modulate neuroinflammation through complement regulation
Interaction between CFH and [amyloid-beta](/proteins/amyloid-beta) may influence plaque formation [5]
Age-Related Macular Degeneration
CFH is the most significant genetic risk factor for AMD:
The Y402H polymorphism (rs1061170) confers 2-4 fold increased risk for AMD [6]
This variant affects binding to choroidal neovascularization membranes
CFH polymorphisms interact with other complement genes (C2, CFB, C3) in AMD risk [7]
CFH deficiency in mouse models leads to retinal complement deposition
Multiple Sclerosis
CFH variants may influence MS susceptibility and disease progression
CSF CFH levels are elevated in MS patients
CFH may regulate demyelination through complement modulation
Anti-CFH antibodies have been detected in some MS patients
Y402H (rs1061170): Most studied AMD-associated variant, affects ligand binding
V62I (rs800292): Common variant with potential protective effects
E936D: Another AMD-associated variant
Population Genetics
Y402H allele frequency varies significantly across populations
Highest frequency in European populations (~35%)
Lower frequency in Asian and African populations
Clinical Significance
Therapeutic Targets
CFH replacement therapy for CFH deficiency (experimental)
CFH inhibitors being developed for AMD treatment
Gene therapy approaches under investigation
Biomarker Potential
CSF CFH levels as potential neurodegenerative disease biomarker
CFH Y402H as genetic risk marker for AMD
Background
The study of Cfh has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.