scholarly journals Systemic complement levels in patients with age-related macular degeneration carrying rare or low frequency variants in the CFH gene

2021 ◽  
Author(s):  
Sarah de Jong ◽  
Anita de Breuk ◽  
Elena B Volokhina ◽  
Bjorn Bakker ◽  
Alejandro Garanto ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Vision Loss ◽  
Rare Variants ◽  
Low Frequency ◽  
Missense Variant ◽  
Factor H ◽  
Age Related Macular Degeneration ◽  
Western World ◽  
Complement Factor ◽  
Age Related

Abstract Age-related macular degeneration (AMD) is a major cause of vision loss among the elderly in the Western world. Genetic variants in the complement factor H (CFH) gene are associated with AMD, but the functional consequences of many of these variants are currently unknown. In this study we aimed to determine the effect of 64 rare and low frequency variants in the CFH gene on systemic levels of factor H (FH) and complement activation marker C3bBbP using plasma samples of 252 carriers and 159 non-carriers. Individuals carrying a heterozygous nonsense, frameshift or missense variant in CFH presented with significantly decreased FH levels, and significantly increased C3bBbP levels in plasma compared to non-carrier controls. FH and C3bBbP plasma levels were relatively stable over time in samples collected during follow-up visits. Decreased FH and increased C3bBbP concentrations were observed in carriers compared to non-carriers of CFH variants among different AMD stages, with the exception of C3bBbP levels in advanced AMD stages, which were equally high in carriers and non-carriers. In AMD families, FH levels were decreased in carriers compared to non-carriers, but C3bBbP levels did not differ. Rare variants in the CFH gene can lead to reduced FH levels or reduced FH function as measured by increased C3bBbP levels. The effects of individual variants in the CFH gene reported in this study will improve the interpretation of rare and low frequency variants observed in AMD patients in clinical practice.

Complement factor H and age-related macular degeneration: the role of glycosaminoglycan recognition in disease pathology

2010 ◽  
Vol 38 (5) ◽  
pp. 1342-1348 ◽  
Author(s):  
Simon J. Clark ◽  
Paul N. Bishop ◽  
Anthony J. Day
Keyword(s):  
Macular Degeneration ◽  
Dermatan Sulfate ◽  
Factor H ◽  
Age Related Macular Degeneration ◽  
Complement Factor H ◽  
Western World ◽  
Complement Factor ◽  
Coat Proteins ◽  
Age Related ◽  
Increased Risk

AMD (age-related macular degeneration) is the major cause of blindness in the western world, associated with the formation of extracellular deposits called drusen in the macula, i.e. the central region of the retina. These drusen contain cellular debris and proteins, including components of the complement system such as the regulator CFH (complement factor H); dysregulation of complement is thought to play a major role in the development of AMD. CFH acts through its capacity to recognize polyanionic structures [e.g. sulfated GAGs (glycosaminoglycans)] found on host tissues, and thereby inactivates any C3b that becomes deposited. Importantly, a common polymorphism in CFH (Y402H) has been strongly associated with an increased risk of AMD. This polymorphism, which causes a tyrosine to histidine coding change, has been shown to alter the binding of CFH to sulfated GAGs, as well as to other ligands including C-reactive protein, necrotic cells and bacterial coat proteins. Of these, the change in the GAG-recognition properties of CFH is likely to be of most significance to AMD. Recent research has revealed that the disease-associated 402H allotype interacts less well (compared with 402Y) with binding sites within the macula (e.g. Bruch's membrane), where the GAGs heparan sulfate and dermatan sulfate play a major role in mediating the interaction with CFH. Reduced binding of the 402H allotype could result in impaired regulation of complement leading to chronic local inflammation that may contribute to the accumulation of drusen and thus the initiation, development and progression of AMD.

scholarly journals Rare Genetic Variants in Jewish Patients Suffering from Age-Related Macular Degeneration

Genes ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 825 ◽  
Author(s):  
Shoshany ◽  
Weiner ◽  
Safir ◽  
Einan-Lifshitz ◽  
Pokroy ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Genetic Variants ◽  
Rare Variants ◽  
Phase 1 ◽  
Mutation Screening ◽  
Factor H ◽  
Age Related Macular Degeneration ◽  
Complement Factor ◽  
Age Related ◽  
Rare Genetic Variants

Purpose: To identify rare genetic variants in early age-related macular degeneration (AMD) utilizing whole-exome sequencing (WES). Methods: Eight non-related early-AMD families of different Jewish ethnicities were ascertained. Initial mutation screening (phase-1) included common complement factor-H (CFH) p.Y402H; and age related maculopathy susceptibility 2 (ARMS2) p.A69S; and rare variants complement factor-I (CFI) p.V412M; and hemicentin1 (HMCN1) c.4163delC identified previously in our population. Four families, whose initial screening for the aforementioned variants was negative, underwent WES (phase-2). Bioinformatics filtering was based on functionality (from a panel of 234 genes with proven or presumed association to AMD); predicted severity; and frequency (rare variants with minor allele frequency <1%). When applicable, further screening for specific rare variants was carried out on additional cases of similar ethnicities and phenotypes (phase-3). Results: Phase-1 identified three families carrying CFI p.V412M mutation. WES analysis detected probable disease-related variants in three out of the remaining families. These included: a family with a variant in PLEKHA1 gene p.S177N; a family with previously reported variant p.R1210C in CFH gene; and two families with the C3 p.R735W variant. Conclusions: Rare, high-penetrance variants have a profound contribution to early-AMD pathogenesis. Utilization of WES in genetic research of multifactorial diseases as AMD, allows a thorough comprehensive analysis with the identification of previously unreported rare variants.

scholarly journals Human complement factor H Y402H polymorphism causes an age-related macular degeneration phenotype and lipoprotein dysregulation in mice

2019 ◽  
Vol 116 (9) ◽  
pp. 3703-3711 ◽  
Author(s):  
Michael Landowski ◽  
Una Kelly ◽  
Mikael Klingeborn ◽  
Marybeth Groelle ◽  
Jin-Dong Ding ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Vision Loss ◽  
Normal Diet ◽  
Factor H ◽  
Age Related Macular Degeneration ◽  
Complement Factor H ◽  
Complement Factor ◽  
Age Related ◽  
Y402h Polymorphism

One of the strongest susceptibility genes for age-related macular degeneration (AMD) is complement factor H (CFH); however, its impact on AMD pathobiology remains unresolved. Here, the effect of the principal AMD-risk–associated CFH variant (Y402H) on the development and progression of age-dependent AMD-like pathologies was determined in vivo. Transgenic mice expressing equal amounts of the full-length normal human CFH Y402 (CFH-Y/0) or the AMD-risk associated CFH H402 (CFH-H/H) variant on a Cfh−/− background were aged to 90 weeks and switched from normal diet (ND) to a high fat, cholesterol-enriched (HFC) diet for 8 weeks. The resulting phenotype was compared with age-matched controls maintained on ND. Remarkably, an AMD-like phenotype consisting of vision loss, increased retinal pigmented epithelium (RPE) stress, and increased basal laminar deposits was detected only in aged CFH-H/H mice following the HFC diet. These changes were not observed in aged CFH-Y/0 mice or in younger (36- to 40-week-old) CFH mice of both genotypes fed either diet. Biochemical analyses of aged CFH mice after HFC diet revealed genotype-dependent changes in plasma and eyecup lipoproteins, but not complement activation, which correlated with the AMD-like phenotype in old CFH-H/H mice. Specifically, apolipoproteins B48 and A1 are elevated in the RPE/choroid of the aged CFH-H/H mice compared with age-matched control CFH-Y/0 fed a HFC diet. Hence, we demonstrate a functional consequence of the Y402H polymorphism in vivo, which promotes AMD-like pathology development and affects lipoprotein levels in aged mice. These findings support targeting lipoproteins as a viable therapeutic strategy for treating AMD.

scholarly journals Rare Variants in the Functional Domains of Complement Factor H Are Associated With Age-Related Macular Degeneration

2015 ◽  
Vol 56 (11) ◽  
pp. 6873 ◽  
Author(s):  
Michael P. Triebwasser ◽  
Elisha D. O. Roberson ◽  
Yi Yu ◽  
Elizabeth C. Schramm ◽  
Erin K. Wagner ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Rare Variants ◽  
Factor H ◽  
Age Related Macular Degeneration ◽  
Complement Factor H ◽  
Functional Domains ◽  
Complement Factor ◽  
Age Related

Complement factor H R1210C among Japanese patients with age-related macular degeneration

2015 ◽  
Vol 59 (5) ◽  
pp. 273-278 ◽  
Author(s):  
Masahiro Miyake ◽  
Masaaki Saito ◽  
Kenji Yamashiro ◽  
Tetsuju Sekiryu ◽  
Nagahisa Yoshimura
Keyword(s):  
Macular Degeneration ◽  
Japanese Patients ◽  
Factor H ◽  
Age Related Macular Degeneration ◽  
Complement Factor H ◽  
Complement Factor ◽  
Age Related

scholarly journals A Review of Completed and Ongoing Complement Inhibitor Trials for Geographic Atrophy Secondary to Age-Related Macular Degeneration

2021 ◽  
Vol 10 (12) ◽  
pp. 2580
Author(s):  
Omar A. Halawa ◽  
Jonathan B. Lin ◽  
Joan W. Miller ◽  
Demetrios G. Vavvas
Keyword(s):  
Macular Degeneration ◽  
Geographic Atrophy ◽  
Age Related Macular Degeneration ◽  
Western World ◽  
Complement Factor ◽  
Complement Protein ◽  
Pivotal Phase ◽  
Complement Inhibition ◽  
Exudative Amd ◽  
Age Related

Age-related macular degeneration (AMD) is a leading cause of irreversible blindness among older adults in the Western world. While therapies exist for patients with exudative AMD, there are currently no approved therapies for non-exudative AMD and its advanced form of geographic atrophy (GA). The discovery of genetic variants in complement protein loci with increased susceptibility to AMD has led to the investigation of the role of complement inhibition in AMD with a focus on GA. Here, we review completed and ongoing clinical trials evaluating the safety and efficacy of these studies. Overall, complement inhibition in GA has yielded mixed results. The inhibition of complement factor D has failed pivotal phase 3 trials. Studies of C3 and C5 inhibition meeting their primary endpoint are limited by high rates of discontinuation and withdrawal in the treatment arm and higher risks of conversion to exudative AMD. Studies evaluating other complement members (CFB, CFH, CFI and inhibitors of membrane attack complex—CD59) are ongoing and could offer other viable strategies.

scholarly journals Oxidative Stress and Mitochondrial Damage in Dry Age-Related Macular Degeneration Like NFE2L2/PGC-1α -/- Mouse Model Evoke Complement Component C5a Independent of C3

Biology ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 622
Author(s):  
Iswariyaraja Sridevi Gurubaran ◽  
Hanna Heloterä ◽  
Stephen Marry ◽  
Ali Koskela ◽  
Juha M. T. Hyttinen ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mouse Model ◽  
Macular Degeneration ◽  
Complement Component ◽  
Factor H ◽  
Age Related Macular Degeneration ◽  
Related Factor ◽  
Complement Factor ◽  
Age Related ◽  
Dry Amd

Aging-associated chronic oxidative stress and inflammation are known to be involved in various diseases, e.g., age-related macular degeneration (AMD). Previously, we reported the presence of dry AMD-like signs, such as elevated oxidative stress, dysfunctional mitophagy and the accumulation of detrimental oxidized materials in the retinal pigment epithelial (RPE) cells of nuclear factor erythroid 2-related factor 2, and a peroxisome proliferator-activated receptor gamma coactivator 1-alpha (NFE2L2/PGC1α) double knockout (dKO) mouse model. Here, we investigated the dynamics of inflammatory markers in one-year-old NFE2L2/PGC1α dKO mice. Immunohistochemical analysis revealed an increase in levels of Toll-like receptors 3 and 9, while those of NOD-like receptor 3 were decreased in NFE2L2/PGC1α dKO retinal specimens as compared to wild type animals. Further analysis showed a trend towards an increase in complement component C5a independent of component C3, observed to be tightly regulated by complement factor H. Interestingly, we found that thrombin, a serine protease enzyme, was involved in enhancing the terminal pathway producing C5a, independent of C3. We also detected an increase in primary acute phase C-reactive protein and receptor for advanced glycation end products in NFE2L2/PGC1α dKO retina. Our main data show C5 and thrombin upregulation together with decreased C3 levels in this dry AMD-like model. In general, the retina strives to mount an orchestrated inflammatory response while attempting to maintain tissue homeostasis and resolve inflammation.

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