title: Determining the population frequency of the CFHR3/CFHR1 deletion at 1q32.
abstract: In this study we have used multiplex ligation-dependent probe amplification (MLPA) to measure the copy number of CFHR3 and CFHR1 in DNA samples from 238 individuals from the UK and 439 individuals from the HGDP-CEPH Human Genome Diversity Cell Line Panel. We have then calculated the allele frequency and frequency of homozygosity for the copy number polymorphism represented by the CFHR3/CFHR1 deletion. There was a highly significant difference between geographical locations in both the allele frequency (X(2)  = 127.7, DF = 11, P-value = 4.97x10(-22)) and frequency of homozygosity (X(2)  = 142.3, DF = 22, P-value = 1.33x10(-19)). The highest frequency for the deleted allele (54.7%) was seen in DNA samples from Nigeria and the lowest (0%) in samples from South America and Japan. The observed frequencies in conjunction with the known association of the deletion with AMD, SLE and IgA nephropathy is in keeping with differences in the prevalence of these diseases in African and European Americans. This emphasises the importance of identifying copy number polymorphism in disease.
authors.affiliation: Institutes of Genetic and Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Lucy V
authors.initials: LV
authors.lastname: Holmes
authors.forename: Lisa
authors.initials: L
authors.lastname: Strain
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Staniforth
authors.forename: Iain
authors.initials: I
authors.lastname: Moore
authors.forename: Kevin
authors.initials: K
authors.lastname: Marchbank
authors.forename: David
authors.initials: D
authors.lastname: Kavanagh
authors.forename: Judith A
authors.initials: JA
authors.lastname: Goodship
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Cordell
authors.forename: Timothy H J
authors.initials: TH
authors.lastname: Goodship
mesh_terms: D003180:Complement C3b Inactivator Proteins / Q000235:genetics*; D005787:Gene Frequency / Q000235:genetics*; D006801:Humans; D017384:Sequence Deletion / Q000235:genetics
chemical_list: C517621:CFHR1 protein, human; D003180:Complement C3b Inactivator Proteins