title: Genetic studies of low-abundance human plasma proteins. XI. Linkage analysis and population genetics of the C1S subcomponent of the first complement component.
abstract: Although subcomponents C1r and C1s of the first complement component, C1, have been established to be in the same linkage group as the proline-rich protein gene cluster on chromosome 12p13.2, no direct analysis of linkage between the C1R and C1S structural gene loci has been available. We have detected through a population screening study 5 families which are heterozygous at the structural loci for both C1R and C1S. Three of the 5 families, 21 individuals, were informative for linkage. A maximum lod score of 1.505 at theta = 0.00 was found in a two-point analysis between C1R and C1S. Ten populations were screened for structural variation at the C1S locus. Only US Whites and a Kodiak Island Eskimo group expressed heterogeneity. The frequencies of the designated alleles, C1S*1 and C1S*2, were 0.992 and 0.007, respectively, in the US White population and 0.998 and 0.002, respectively, in the Kodiak Island Eskimo population. In addition, the product of a putative new allele, designated C1S*4, was observed in a single US White individual but segregation of this variant was not observed in the limited family data available.
authors.affiliation: Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, Pa.
authors.forename: L A
authors.initials: LA
authors.lastname: Lyons
authors.forename: M I
authors.initials: MI
authors.lastname: Kamboh
authors.forename: R E
authors.initials: RE
authors.lastname: Ferrell
mesh_terms: D001798:Blood Proteins / Q000235:genetics*; D003166:Complement Activating Enzymes / Q000235:genetics*; D003172:Complement C1 / Q000235:genetics; D015923:Complement C1r; D003173:Complement C1s / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D008040:Genetic Linkage; D005828:Genetics, Population; D006801:Humans; D008297:Male; D010375:Pedigree; D010641:Phenotype; D044469:Racial Groups; D014481:United States
chemical_list: D001798:Blood Proteins; D003172:Complement C1; D003166:Complement Activating Enzymes; D015923:Complement C1r; D003173:Complement C1s