title: Sequence and Expression of Complement Factor H Gene Cluster Variants and Their Roles in Age-Related Macular Degeneration Risk.
abstract: To investigate how potentially functional genetic variants are coinherited on each of four common complement factor H (CFH) and CFH-related gene haplotypes and to measure expression of these genes in eye and liver tissues.
  
  
  
  We sequenced the CFH region in four individuals (one homozygote for each of four common CFH region haplotypes) to identify all genetic variants. We studied associations between the haplotypes and AMD phenotypes in 2157 cases and 1150 controls. We examined RNA-seq profiles in macular and peripheral retina and retinal pigment epithelium/choroid/sclera (RCS) from eight eye donors and three liver samples.
  
  
  
  The haplotypic coinheritance of potentially functional variants (including missense variants, novel splice sites, and the CFHR3-CFHR1 deletion) was described for the four common haplotypes. Expression of the short and long CFH transcripts differed markedly between the retina and liver. We found no expression of any of the five CFH-related genes in the retina or RCS, in contrast to the liver, which is the main source of the circulating proteins.
  
  
  
  We identified all genetic variants on common CFH region haplotypes and described their coinheritance. Understanding their functional effects will be key to developing and stratifying AMD therapies. The small scale of our expression study prevented us from investigating the relationships between CFH region haplotypes and their expression, and it will take time and collaboration to develop epidemiologic-scale studies. However, the striking difference between systemic and ocular expression of complement regulators shown in this study suggests important implications for the development of intraocular and systemic treatments.
authors.affiliation: Formerly of Centre for Public Health Queen's University Belfast, Belfast, United Kingdom.
authors.forename: Anne E
authors.initials: AE
authors.lastname: Hughes
authors.affiliation: Centre for Public Health, Queen's University Belfast, Belfast, United Kingdom.
authors.forename: Stephen
authors.initials: S
authors.lastname: Bridgett
authors.affiliation: Centre for Public Health, Queen's University Belfast, Belfast, United Kingdom.
authors.forename: Weihua
authors.initials: W
authors.lastname: Meng
authors.affiliation: Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States.
authors.forename: Mingyao
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Ophthalmology, University of Alabama, Birmingham, Alabama, United States.
authors.forename: Christine A
authors.initials: CA
authors.lastname: Curcio
authors.affiliation: Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania, United States.
authors.forename: Dwight
authors.initials: D
authors.lastname: Stambolian
authors.affiliation: Centre for Public Health, Queen's University Belfast, Belfast, United Kingdom.
authors.forename: Declan T
authors.initials: DT
authors.lastname: Bradley
mesh_terms: D002829:Choroid / Q000378:metabolism* / Q000473:pathology; D017242:Complement Factor H / Q000096:biosynthesis / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation; D014644:Genetic Variation; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D008268:Macular Degeneration / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012313:RNA / Q000235:genetics*; D055213:Retinal Pigment Epithelium / Q000378:metabolism* / Q000473:pathology; D012590:Sclera / Q000378:metabolism* / Q000473:pathology
chemical_list: C493495:CFH protein, human; D012313:RNA; D017242:Complement Factor H