Complement factor H deficiency and endocapillary glomerulonephritis due to paternal isodisomy and a novel factor H mutation

Complement factor H in molecular regulation of angiogenesis

Angiogenesis, the process of formation of new capillaries from existing blood vessels, is required for multiple physiological and pathological processes. Complement factor H (CFH) is a plasma protein that inhibits the alternative pathway of the complement system. Loss of CFH enhances the alternative pathway and increases complement activation fragments with pro-angiogenic capacity, including complement 3a, complement 5a, and membrane attack complex. CFH protein contains binding sites for C-reactive protein, malondialdehyde, and endothelial heparan sulfates. Dysfunction of CFH prevents its interaction with these molecules and initiates pro-angiogenic events. Mutations in the CFH gene have been found in patients with age-related macular degeneration characterized by choroidal neovascularization. The Cfh-deficient mice show an increase in angiogenesis, which is decreased by administration of recombinant CFH protein. In this review, we summarize the molecular mechanisms of the anti-angiogenic effects of CFH and the regulatory mechanisms of CFH expression. The therapeutic potential of recombinant CFH protein in angiogenesis-related diseases has also been discussed.

Predictive prognostic value of glomerular C3 deposition in IgA nephropathy

BACKGROUND

IgAN is the most common primary glomerulonephritis worldwide. However, the pathogenesis of IgAN remains unknown. Currently, there is evidence that C3 deposition plays a role in disease development. This study aimed to investigate clinical, pathological features, and prognosis of adult IgAN patients with C3 deposition, as well as explore the role of complement activation in disease progression.

METHODS

A total of 821 patients with biopsy-proven IgAN were included in this study. Patients were divided into three different groups according to their C3 deposition intensity. Clinical and pathological characteristics were compared between groups. Logistic analysis was used to estimate the relationship between C3 deposition and the Oxford scoring system. Univariate and multivariate Cox proportional hazard regression models were used to analyze the effect of the presence of C3 deposits on the prognosis of patients with IgA nephropathy. Kaplan-Meier survival analysis was used to evaluate the cumulative incidence of renal progression between groups.

RESULTS

Patients with C3 deposition exhibited more severe clinical and pathological features and had a higher score according to the Oxford scoring system. With the increasing intensity of C3 deposition, patients present more hematuria, crescents, heavier interstitial inflammatory cell infiltration and a higher score on segmental sclerosis lesions. Logistic regression identified a positive relationship between C3 deposition and histopathology. Univariate and multivariate Cox regression indicated that C3 deposition was an independent risk factor for IgAN severity. The Kaplan-Meier survival curves indicated that patients with positive C3 deposition had a worse prognosis compared to those without C3 deposition.

CONCLUSIONS

Patients with positive glomerular C3 deposition presented with more severe clinical and histopathological characteristics and a higher score on the Oxford scoring system. With the increasing intensity of C3 deposition, IgAN patients were more likely to present with high level of microscopic hematuria, fibrous crescents, interstitial inflammatory cell infiltration, and a higher score on segmental sclerosis lesions. C3 deposition at the time of renal biopsy is likely an independent risk factor for IgA nephropathy severity and progression.

Deletion of ERF and CIC causes abnormal skull morphology and global developmental delay

The ETS2 repressor factor (ERF) is a transcription factor in the RAS-MEK-ERK signal transduction cascade that regulates cell proliferation and differentiation, and pathogenic sequence variants in the ERF gene cause variable craniosynostosis inherited in an autosomal dominant pattern. The reported ERF variants are largely loss-of-function, implying haploinsufficiency as a primary disease mechanism; however, ERF gene deletions have not been reported previously. Here we describe three probands with macrocephaly, craniofacial dysmorphology, and global developmental delay. Clinical genetic testing for fragile X and other relevant sequencing panels were negative; however, chromosomal microarray identified heterozygous deletions (63.7-583.2 kb) on Chromosome 19q13.2 in each proband that together included five genes associated with Mendelian diseases (ATP1A3, ERF, CIC, MEGF8, and LIPE). Parental testing indicated that the aberrations were apparently de novo in two of the probands and were inherited in the one proband with the smallest deletion. Deletion of ERF is consistent with the reported loss-of-function ERF variants, prompting clinical copy-number-variant classifications of likely pathogenic. Moreover, the recent characterization of heterozygous loss-of-function CIC sequence variants as a cause of intellectual disability and neurodevelopmental disorders inherited in an autosomal dominant pattern is also consistent with the developmental delays and intellectual disabilities identified among the two probands with CIC deletions. Taken together, this case series adds to the previously reported patients with ERF and/or CIC sequence variants and supports haploinsufficiency of both genes as a mechanism for a variable syndromic cranial phenotype with developmental delays and intellectual disability inherited in an autosomal dominant pattern.

Novel Clinical and Radiological Findings in a Family with Autosomal Recessive Omodysplasia

Autosomal recessive omodysplasia (GPC6-related) is a rare short-limb skeletal dysplasia caused by biallelic mutations in the GPC6 gene. Affected individuals manifest with rhizomelic short stature, decreased mobility of elbow and knee joints as well as craniofacial anomalies. Both upper and lower limbs are severely affected. These manifestations contrast with normal height and limb shortening restricted to the arms in autosomal dominant omodysplasia (FZD2-related). Here, we report 2 affected brothers of Pakistani descent from Denmark with GPC6-related omodysplasia, aiming to highlight the clinical and radiological findings. A homozygous deletion of exon 6 in the GPC6 gene was detected. The pathognomonic radiological findings were distally tapered humeri and femora as well as severe proximal radioulnar diastasis. On close observations, we identified a recurrent and not previously described type of abnormal patterning in all long bones.

Interpretation of Autosomal Recessive Kidney Diseases With "Presumed Homozygous" Pathogenic Variants Should Consider Technical Pitfalls

Background: A false interpretation of homozygosity for pathogenic variants causing autosomal recessive disorders can lead to improper genetic counseling. The aim of this study was to demonstrate the underlying etiologies of presumed homozygous disease-causing variants harbored in six unrelated children with five different genetic renal diseases when the same variant was identified in a heterozygous state in only one of the two parents from each family using direct sequencing. Methods: Peripheral blood genomic DNA samples were extracted. Six short tandem repeats were used to verify the biological relationships between the probands and their parents. Quantitative PCR was performed to detect mutant exons with deletions. Single nucleotide polymorphism analysis and genotyping with polymorphic microsatellite markers were performed to identify uniparental disomy (UPD). Results: Each proband and his/her parents had biological relationships. Patients 2, 4, and 6 were characterized by large deletions encompassing a missense/small deletion in DGKE, NPHP1, and NPHS1, respectively. Patients 1 and 5 were caused by segmental UPD in NPHS2 and SMARCAL1, respectively. In patient 6, maternal UPD, mosaicism in paternal sperm or de novo variant in NPHP1 could not be ruled out. Conclusions: When a variant analysis report shows that a patient of non-consanguineous parents has a pathogenic presumed homozygous variant, we should remember the need to assess real homozygosity for the variant, and a segregation analysis of the variants within the parental DNAs and comprehensive molecular tests to evaluate the potential molecular etiologies, such as a point variant and an overlapping exon deletion, UPD, germline mosaicism and de novo variant, are crucial.

C3-Glomerulopathy Autoantibodies Mediate Distinct Effects on Complement C3- and C5-Convertases

C3 glomerulopathy (C3G) is a severe kidney disease, which is caused by defective regulation of the alternative complement pathway. Disease pathogenesis is heterogeneous and is caused by both autoimmune and genetic factors. Here we characterized IgG autoantibodies derived from 33 patients with autoimmune C3 glomerulopathy. Serum antibodies from all 33 patients as well as purified IgGs bound to the in vitro assembled C3-convertase. Noteworthy, two groups of antibodies were identified: group 1 with strong (12 patients) and group 2 with weak binding C3-convertase autoantibodies (22 patients). C3Nef, as evaluated in a standard C3Nef assay, was identified in serum from 19 patients, which included patients from group 1 as well as group 2. The C3-convertase binding profile was independent of C3Nef. Group 1 antibodies, but not the group 2 antibodies stabilized the C3-convertase, and protected the enzyme from dissociation by Factor H. Also, only group 1 antibodies induced C3a release. However, both group 1 and group 2 autoantibodies bound to the C5-convertase and induced C5a generation, which was inhibited by monoclonal anti-C5 antibody Eculizumab in vitro. In summary, group 1 antibodies are composed of C3Nef and C5Nef antibodies and likely over-activate the complement system, as seen in hemolytic assays. Group 2 antibodies show predominantly C5Nef like activities and stabilize the C5 but not the C3-convertase. Altogether, these different profiles not only reveal a heterogeneity of the autoimmune forms of C3G (MPGN), they also show that in diagnosis of C3G not all autoimmune forms are identified and thus more vigorous autoantibody testing should be performed.

Loss-of-Function Mutations in the CFH Gene Affecting Alternatively Encoded Factor H-like 1 Protein Cause Dominant Early-Onset Macular Drusen

Purpose

To characterize the molecular mechanism underpinning early-onset macular drusen (EOMD), a phenotypically severe subtype of age-related macular degeneration (AMD), in a subgroup of patients.

Design

Multicenter case series, in vitro experimentation, and retrospective analysis of previously reported variants.

Participants

Seven families with apparently autosomal dominant EOMD.

Methods

Patients underwent a comprehensive ophthalmic assessment. Affected individuals from families A, B, and E underwent whole exome sequencing. The probands from families C, D, F, and G underwent Sanger sequencing analysis of the complement factor H (CFH) gene. Mutant recombinant factor H like-1 (FHL-1) proteins were expressed in HEK293 cells to assess the impact on FHL-1 expression and function. Previously reported EOMD-causing variants in CFH were reviewed.

Main Outcome Measures

Detailed clinical phenotypes, genomic findings, in vitro characterization of mutation effect on protein function, and postulation of the pathomechanism underpinning EOMD.

Results

All affected participants demonstrated bilateral drusen. The earliest reported age of onset was 16 years (median, 46 years). Ultra-rare (minor allele frequency [MAF], ≤0.0001) CFH variants were identified as the cause of disease in each family: CFH c.1243del, p.(Ala415ProfsTer39) het; c.350+1G→T het; c.619+1G→A het, c.380G→A, p.(Arg127His) het; c.694C→T p.(Arg232Ter) het (identified in 2 unrelated families in this cohort); and c.1291T→A, p.(Cys431Ser). All mutations affect complement control protein domains 2 through 7, and thus are predicted to impact both FHL-1, the predominant isoform in Bruch’s membrane (BrM) of the macula, and factor H (FH). In vitro analysis of recombinant proteins FHL-1_R127H, FHL-1_A415f/s, and FHL-1_C431S demonstrated that they are not secreted, and thus are loss-of-function proteins. Review of 29 previously reported EOMD-causing mutations found that 75.8% (22/29) impact FHL-1 and FH. In total, 86.2% (25/29) of EOMD-associated variants cause haploinsufficiency of FH or FHL-1.

Conclusions

Early-onset macular drusen is an underrecognized, phenotypically severe subtype of AMD. We propose that haploinsufficiency of FHL-1, the main regulator of the complement pathway in BrM, where drusen develop, is an important mechanism underpinning the development of EOMD in a number of cases. Understanding the molecular basis of EOMD will shed light on AMD pathogenesis given their pathologic similarities.

Orbital precursor B-lymphoblastic lymphoma involving the extraocular muscles in a 56-year-old male and a review of the literature

The aim of the present study was to describe a rare case of orbital precursor B-lymphoblastic lymphoma (B-LBL) in an adult. A 56-year-old male in complete remission of a gastric precursor B-LBL was referred to our orbital clinic due to rapid development of left-sided painless periorbital swelling, diplopia, and proptosis. Complete ophthalmoplegia was observed. Notably, magnetic resonance imaging showed swelling of the medial and inferior rectus muscles in the left orbit and biopsies were performed. Following histological diagnosis of precursor B-LBL, the patient was treated with radiotherapy (2Gy × 20) and chemotherapy according to the NOPHO ALL 2008 protocol. The disease progressed and the patient succumbed after 5 months. Histomorphologically, a lymphoblastic infiltrate was observed within the skeletal muscle tissue. The tumor cells were small and immature, and stained strongly for cluster of differentiating (CD)10, CD79a, paired box 5 and B cell lymphoma-2. The Ki-67 proliferative index was 90%. Multiplex ligation-dependent probe amplification and array comparative genomic hybridization detected whole chromosomal gain of X and 12, and both hemizygous and homozygous deletion on 9p comprising cyclin dependent kinase inhibitor 2A/B. Furthermore, array comparative genomic hybridization detected copy number imbalances consisting of focal or smaller deletions on chromosomes 1, 9, 10, 11 and 20. The final diagnosis was precursor B-LBL relapse in the extraocular muscles. Orbital precursor B-LBL is extremely rare in adults, and the diagnosis may be challenging to make. It is recommended to obtain material for cytogenetic and molecular analyses.

Complements are involved in alcoholic fatty liver disease, hepatitis and fibrosis

The complement system is a key component of the body's immune system. When abnormally activated, this system can induce inflammation and damage to normal tissues and participate in the development and progression of a variety of diseases. In the past, many scholars believed that alcoholic liver disease (ALD) is induced by the stress of ethanol on liver cells, including oxidative stress and dysfunction of mitochondria and protease bodies, causing hepatocyte injury and apoptosis. Recent studies have shown that complement activation is also involved in the genesis and development of ALD. This review focuses on the roles of complement activation in ALD and of therapeutic intervention in complement-activation pathways. We intend to provide new ideas on the diagnosis and treatment of ALD.

Neonatal hyperinsulinemic hypoglycemia in a patient with 9p deletion syndrome

We report the clinical and neuroradiological findings in a young boy harboring the 9p deletion syndrome including the novel findings of thalamic infarction and germinal matrix haemorrhage and neonatal hyperinsulinemic hypoglycemia. Both the hypoglycemic events and the ventriculomegaly found in this patient have previously only been reported in two patients, while the thalamic infarction and germinal matrix haemorrhage are novel features.

Atypical hemolytic uremic syndrome and C3 glomerulopathy: conclusions from a "Kidney Disease: Improving Global Outcomes" (KDIGO) Controversies Conference

In both atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy (C3G) complement plays a primary role in disease pathogenesis. Herein we report the outcome of a 2015 Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference where key issues in the management of these 2 diseases were considered by a global panel of experts. Areas addressed included renal pathology, clinical phenotype and assessment, genetic drivers of disease, acquired drivers of disease, and treatment strategies. In order to help guide clinicians who are caring for such patients, recommendations for best treatment strategies were discussed at length, providing the evidence base underpinning current treatment options. Knowledge gaps were identified and a prioritized research agenda was proposed to resolve outstanding controversial issues.

Complement inhibition in C3 glomerulopathy

C3 glomerulopathy (C3G) describes a spectrum of glomerular diseases defined by shared renal biopsy pathology: a predominance of C3 deposition on immunofluorescence with electron microscopy permitting disease sub-classification. Complement dysregulation underlies the observed pathology, a causal relationship that is supported by well described studies of genetic and acquired drivers of disease. In this article, we provide an overview of the features of C3G, including a discussion of disease definition and a review of the causal role of complement. We discuss molecular markers of disease and how biomarkers are informing our evolving understanding of underlying pathology. Research advances are laying the foundation for complement inhibition as a targeted approach to treatment of C3G.

Kidney Disease Caused by Dysregulation of the Complement Alternative Pathway: An Etiologic Approach

Kidney diseases caused by genetic or acquired dysregulation of the complement alternative pathway (AP) are traditionally classified on the basis of clinical presentation (atypical hemolytic uremic syndrome as thrombotic microangiopathy), biopsy appearance (dense deposit disease and C3 GN), or clinical course (atypical postinfectious GN). Each is characterized by an inappropriate activation of the AP, eventuating in renal damage. The clinical diversity of these disorders highlights important differences in the triggers, the sites and intensity of involvement, and the outcome of the AP dysregulation. Nevertheless, we contend that these diseases should be grouped as disorders of the AP and classified on an etiologic basis. In this review, we define different pathophysiologic categories of AP dysfunction. The precise identification of the underlying abnormality is the key to predict the response to immune suppression, plasma infusion, and complement-inhibitory drugs and the outcome after transplantation. In a patient with presumed dysregulation of the AP, the collaboration of the clinician, the renal pathologist, and the biochemical and genetic laboratory is very much encouraged, because this enables the elucidation of both the underlying pathogenesis and the optimal therapeutic approach.

Monozygotic twins with a de novo 0.32 Mb 16q24.3 deletion, including TUBB3 presenting with developmental delay and mild facial dysmorphism but without overt brain malformation

Nervous system development is highly dependent on the function of microtubules, which are assembled from tubulin heterodimers containing several α- and β-tubulin isotypes encoded by separate genes. A spectrum of neurological disorders with malformations of the central nervous system has recently been associated with missense mutations in this group of genes. Here, we report two patients, monozygotic twins, carrying a de novo 0.32 Mb deletion of chromosome 16q24.3 including the TUBB3 gene. The patients presented with global developmental delay, mild facial dysmorphism, secondary microcephaly, and mild spastic diplegia. Cerebral magnetic resonance imaging of the patients did not reveal cortical malformations, malformations of the corticospinal tracts, basal ganglia, corpus callosum, or optic nerves. This observation is in contrast to the group of neurological disorders that are associated with heterozygous missense mutations in genes encoding different neuronal α- and β-tubulin isotypes, termed tubulinopathies. On the background of current knowledge regarding the function and genotype-phenotype correlations of mutations in the neuronal tubulin isotypes, the clinical and diagnostic findings in these patients are discussed. To our knowledge, this is the first report of patients with a de novo deletion of the TUBB3 gene. The lack of cortical or other cerebral malformations supports the current hypothesis that TUBB3-related tubulinopathies are caused by altered protein function.

The role of complement in C3 glomerulopathy

C3 glomerulopathy describes a spectrum of disorders with glomerular pathology associated with C3 cleavage product deposition and with defective complement action and regulation (Fakhouri et al., 2010; Sethi et al., 2012b). Kidney biopsies from these patients show glomerular accumulation or deposition of C3 cleavage fragments, but no or minor deposition of immunoglobulins (Appel et al., 2005; D'Agati and Bomback, 2012; Servais et al., 2007; Sethi and Fervenza, 2011). At present the current situation asks for a better definition of the underlining disease mechanisms, for precise biomarkers, and for a treatment for this disease. The complement system is a self activating and propelling enzymatic cascade type system in which inactive, soluble plasma components are activated spontaneously and lead into an amplification loop (Zipfel and Skerka, 2009). Activation of the alternative pathway is spontaneous, occurs by default, and cascade progression leads to amplification by complement activators. The system however is self-controlled by multiple regulators and inhibitors, like Factor H that control cascade progression in fluid phase and on surfaces. The activated complement system generates a series of potent effector components and activation products, which damage foreign-, as well as modified self cells, recruit innate immune cells to the site of action, coordinate inflammation and the response of the adaptive immune system in form of B cells and T lymphocytes (Kohl, 2006; Medzhitov and Janeway, 2002; Ogden and Elkon, 2006; Carroll, 2004; Kemper and Atkinson, 2007; Morgan, 1999; Muller-Eberhard, 1986; Ricklin et al., 2010). Complement controls homeostasis and multiple reactions in the vertebrate organism including defense against microbial infections (Diaz-Guillen et al., 1999; Mastellos and Lambris, 2002; Nordahl et al., 2004; Ricklin et al., 2010). In consequence defective control of the spontaneous self amplifying cascade or regulation is associated with numerous human disorders (Ricklin and Lambris, 2007; Skerka and Zipfel, 2008; Zipfel et al., 2006). Understanding the exact action and regulation of this sophisticated homeotic cascade system is relevant to understand disease pathology of various complement associated human disorders. Furthermore this knowledge is relevant for a better diagnosis and appropriate therapy. At present diagnosis of C3 glomerulopathy is primarily based on the kidney biopsy, and histological, immmunohistological and electron microscopical evaluation (D'Agati and Bomback, 2012; Fakhouri et al., 2010; Medjeral-Thomas et al., 2014a,b; Sethi et al., 2012b). The challenge is to define the actual cause of the diverse glomerular changes or damages, to define how C3 deposition results in the reported glomerular changes, the location of the cell damage and the formation of deposits.

Maternal uniparental isodisomy causing autosomal recessive GM1 gangliosidosis: a clinical report

Uniparental disomy is a genetic cause of disease that may result in the inheritance of an autosomal recessive condition. A child with developmental delay and hypotonia was seen and found to have severely abnormal myelination. Lysosomal enzyme testing identified an isolated deficiency of beta-galactosidase. Subsequently, homozygous missense mutations in the galactosidase, beta 1 (GLB1) gene on chromosome 3 were found. Parental testing confirmed inheritance of two copies of the same mutated maternal GLB1 gene, and no paternal copy. SNP analysis was also done to confirm paternity. The patient was ultimately diagnosed with autosomal recessive GM1 gangliosidosis caused by maternal uniparental isodisomy. We provide a review of this patient and others in which uniparental disomy (UPD) of a non-imprinted chromosome unexpectedly caused an autosomal recessive condition. This is the first case of GM1 gangliosidosis reported in the literature to have been caused by UPD. It is important for genetic counselors and other health care providers to be aware of the possibility of autosomal recessive disease caused by UPD. UPD as a cause of autosomal recessive disease drastically changes the recurrence risk for families, and discussions surrounding UPD can be complex. Working with families to understand UPD when it occurs requires a secure and trusting counselor-family relationship.

Dense deposit disease and C3 glomerulopathy

C3 glomerulopathy refers to those renal lesions characterized histologically by predominant C3 accumulation within the glomerulus, and pathogenetically by aberrant regulation of the alternative pathway of complement. Dense deposit disease is distinguished from other forms of C3 glomerulopathy by its characteristic appearance on electron microscopy. The extent to which dense deposit disease also differs from other forms of C3 glomerulopathy in terms of clinical features, natural history, and outcomes of treatment including renal transplantation is less clear. We discuss the pathophysiology of C3 glomerulopathy, with evidence for alternative pathway dysregulation obtained from affected individuals and complement factor H (Cfh)-deficient animal models. Recent linkage studies in familial C3 glomerulopathy have shown genomic rearrangements in the Cfh-related genes, for which the novel pathophysiologic concept of Cfh deregulation has been proposed.

Genotype/phenotype correlations in complement factor H deficiency arising from uniparental isodisomy

We report a male infant who presented at 8 months of age with atypical hemolytic uremic syndrome (aHUS) responsive to plasma therapy. Investigation showed him to have complement factor H (CFH) deficiency associated with a homozygous CFH mutation (c.2880delT [p.Phe960fs]). Mutation screening of the child's parents revealed that the father was heterozygous for this change but that it was not present in his mother. Chromosome 1 uniparental isodisomy of paternal origin was confirmed by genotyping chromosome 1 SNPs. CD46 SNP genotyping was undertaken in this individual and another patient with CFH deficiency associated with chromosome 1 uniparental isodisomy. This showed a homozygous aHUS risk haplotype (CD46GGAAC) in the patient with aHUS and a homozygous glomerulonephritis risk haplotype (CD46AAGGT) in the patient with endocapillary glomerulonephritis. We also showed that FHL-1 (factor H-like protein 1) was present in the patient with aHUS and absent in the patient with glomerulonephritis. This study emphasizes that modifiers such as CD46 and FHL-1 may determine the kidney phenotype of patients who present with homozygous CFH deficiency.

Recent insights into C3 glomerulopathy

‘C3 glomerulopathy’ is a recent disease classification comprising several rare types of glomerulonephritis (GN), including dense deposit disease (DDD), C3 glomerulonephritis (C3GN) and CFHR5 nephropathy. These disorders share the key histological feature of isolated complement C3 deposits in the glomerulus. A common aetiology involving dysregulation of the alternative pathway (AP) of complement has been elucidated in the past decade, with genetic defects and/or autoantibodies able to be identified in a proportion of patients. We review the clinical and histological features of C3 glomerulopathy, relating these to underlying molecular mechanisms. The role of uncontrolled C3 activation in pathogenesis is emphasized, with important lessons from animal models. Methods, advantages and limitations of gene testing in the assessment of individuals or families with C3 glomerulopathy are discussed. While no therapy has yet been shown consistently effective, clinical evaluation of agents targeting specific components of the complement system is ongoing. However, limits to current knowledge regarding the natural history and the appropriate timing and duration of proposed therapies need to be addressed.

Complement factor H genotypes impact risk of age-related macular degeneration by interaction with oxidized phospholipids

The rs1061170T/C variant encoding the Y402H change in complement factor H (CFH) has been identified by genome-wide association studies as being significantly associated with age-related macular degeneration (AMD). However, the precise mechanism by which this CFH variant impacts the risk of AMD remains largely unknown. Oxidative stress plays an important role in many aging diseases, including cardiovascular disease and AMD. A large amount of oxidized phospholipids (oxPLs) are generated in the eye because of sunlight exposure and high oxygen content. OxPLs bind to the retinal pigment epithelium and macrophages and strongly activate downstream inflammatory cascades. We hypothesize that CFH may impact the risk of AMD by modulating oxidative stress. Here we demonstrate that CFH binds to oxPLs. The CFH 402Y variant of the protective rs1061170 genotype binds oxPLs with a higher affinity and exhibits a stronger inhibitory effect on the binding of oxPLs to retinal pigment epithelium and macrophages. In addition, plasma from non-AMD subjects with the protective genotype has a lower level of systemic oxidative stress measured by oxPLs per apolipoprotein B (oxPLs/apoB). We also show that oxPL stimulation increases expression of genes involved in macrophage infiltration, inflammation, and neovascularization in the eye. OxPLs colocalize with CFH in drusen in the human AMD eye. Subretinal injection of oxPLs induces choroidal neovascularization in mice. In addition, we show that the CFH risk allele confers higher complement activation and cell lysis activity. Together, these findings suggest that CFH influences AMD risk by modulating oxidative stress, inflammation, and abnormal angiogenesis.