title: Haptoglobin duplicon, hemoglobin, and vitamin C: analyses in the british women's heart and health study and Caerphilly prospective study.
abstract: BACKGROUND
  Haptoglobin acts as an antioxidant by limiting peroxidative tissue damage by free hemoglobin. The haptoglobin gene allele Hp2 comprises a 1.7 kb partial duplication. Relative to allele Hp1, Hp2 carriers form protein multimers, suboptimal for hemoglobin scavenging.
  
  
  OBJECTIVE
  To examine the association of haptoglobin genotype with a range of phenotypes, with emphasis on vitamin C and hemoglobin levels.
  
  
  METHODS
  We applied a quantitative PCR assay for the duplication junction to two population cohorts including 2747 British women and 1198 British men. We examined the association of haptoglobin duplicon copy number with hemoglobin and vitamin C and used the copy number to complete a phenome scan.
  
  
  RESULTS
  Hemoglobin concentrations were greater in those with Hp2,2 genotype, in women only (Hp1,1 13.45 g/dL, Hp1,2 13.49 g/dL, Hp2,2 13.61 g/dL; P = 0.002), though statistically there was no evidence of a difference between the sexes (z value = 1.2, P = 0.24). Haptoglobin genotype was not associated with vitamin C or any other phenotype in either cohort.
  
  
  CONCLUSIONS
  Our results do not support association of haptoglobin genotype with vitamin C or with other phenotypes measured in two population cohorts. The apparent association between haptoglobin genotype and hemoglobin in the women's cohort merits further investigation.
authors.affiliation: Bristol Genetic Epidemiology Laboratory, School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK.
authors.forename: Philip A I
authors.initials: PA
authors.lastname: Guthrie
authors.affiliation: Bristol Genetic Epidemiology Laboratory, School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK.
authors.forename: Mohammad R
authors.initials: MR
authors.lastname: Abdollahi
authors.affiliation: Bristol Genetic Epidemiology Laboratory, School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK ; MRC Integrative Epidemiology Unit (IEU), University of Bristol, Bristol BS8 2BN, UK.
authors.forename: Tom
authors.initials: T
authors.lastname: Gaunt
authors.affiliation: MRC Integrative Epidemiology Unit (IEU), University of Bristol, Bristol BS8 2BN, UK.
authors.forename: Debbie A
authors.initials: DA
authors.lastname: Lawlor
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol BS8 2PS, UK.
authors.forename: Yoav
authors.initials: Y
authors.lastname: Ben-Shlomo
authors.affiliation: Institute of Primary Care & Public Health, Cardiff University School of Medicine, Cardiff CF14 4XN, UK.
authors.forename: John
authors.initials: J
authors.lastname: Gallacher
authors.affiliation: MRC Integrative Epidemiology Unit (IEU), University of Bristol, Bristol BS8 2BN, UK.
authors.forename: George
authors.initials: G
authors.lastname: Davey Smith
authors.affiliation: Bristol Genetic Epidemiology Laboratory, School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK.
authors.forename: Ian N M
authors.initials: IN
authors.lastname: Day
authors.affiliation: Bristol Genetic Epidemiology Laboratory, School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK.
authors.forename: Santiago
authors.identifier: 0000-0001-6551-932X
authors.initials: S
authors.lastname: Rodriguez
mesh_terms: D001205:Ascorbic Acid / Q000097:blood*; D005260:Female; D018628:Gene Dosage; D020440:Gene Duplication; D005787:Gene Frequency; D056726:Genetic Association Studies; D006242:Haptoglobins / Q000235:genetics*; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012727:Sex Characteristics; D014852:Wales
chemical_list: C485359:HP protein, human; D006242:Haptoglobins; D006454:Hemoglobins; D001205:Ascorbic Acid