Chromosome 21 analysis. (a) Nonparametric linkage (NPL) curve generated by genehunter (v2.5.1) for chromosome 21 (36, 37). Markers are indicated. Markers are shown from the p to q telomeres, and the CRF2 family is located at ≈22.5 cM. (b) Diagrammatic representation of the CRF2 family of genes found at Chr 21q22. Solid arrows represent polymorphisms typed in this study, and the dashed line represents the expanded region in which the genes are located. SNPs resulting in amino acid changes are shown in bold, and microsatellites are in italics.

Evidence of functionality of IFN-AR2-F8S amino acid substitution. (a) Details of relative quantification of transcript levels in heterozygotes for the IFN-AR2 gene. Values used are the RNA expression level divided by the genomic DNA level to control for relative assay efficiency. The data are shown as plots describing the mean ± 2 SE. All data were analyzed by using a Student’s t test after testing for normality of data (version 12; SPSS, Chicago). (b) FACS analysis of cell surface receptor expression. The gating threshold is set at the level exceeded by <5% of untransfected cells, and the proportion of cells exceeding the threshold is given in each case. IFN-AR2 expression in U5a cells transfected with either IFN-AR2-F or IFN-AR2-S. (c) IFN-AR2 expression of EBV-transformed B cell lines of known genotypes. (d) MHC class I expression induced by IFN-α2b in U5a cells expressing either allele of the IFN-AR2 gene and controls. (e) Antiviral responses induced by IFN-α2b in U5a cells expressing either allele of the IFN-AR2 gene and controls.

Linkage disequilibrium (LD) results from graphical overview of linkage disequilibrium (GOLD) (10). The key shows the color scale representing increasing D′ from dark blue (D′ < 0.1) through to red (D′ > 0.9). Markers shown from left to right areas follows: 1, IFN-α-R2-hCV2443221; 2, IFN-α-R2-hCV11354048; 3, IFN-α-R2-rs2300370; 4, IFN-α-R2-rs2448412; 5, IFN-α-R2-rs3153; 6, IFN-α-R2-F8S; 7, IFN-α-R2-F10V; 8, IFN-α-R2-A285T; 9, IL-10RB-K47E; 10, IL-10RB-CA1; 11, IL-10RB-CA2; 12, IL-10RB-1165; 13, IL-10RB-1797; 14, IFN-α-R1-(-408); 15, IFN-α-R1-GT; 16, IFN-α-R1–17470; 17, IFN-α-R1-L168V; 18, IFN-α-R1-IVS; 19, IFN-α-R1–30715; 20, IFN-γ-R2-R64Q; 21, IFN-γ-R2–2080; and 22, IFN-γ-R2–2087.

Evidence of functionality of IL-10RB-K47E amino acid substitution. (a) Details of relative quantification of transcript levels in heterozygotes for the IL-10RB gene. Values used are the RNA expression level divided by the genomic DNA level to control for relative assay efficiency. The data are shown as plots describing the mean ± 2 SE. All data were analyzed by using a Student’s t test after testing for normality of data (version 12; SPSS, Chicago). (b) Density plots showing FACS analysis of cell surface receptor expression. The gating threshold is set at the level exceeded by <5% of untransfected cells, and the proportion of cells exceeding the threshold is given in each case. IL-10RB expression on the cell surface of Huh7 cells transfected with either IL-10RB-K or IL-10RB-E. (c) IL-10-mediated inhibition of LPS-induced TNF-α expression by IL-10RB-K47E genotype. The concentration of IL-10 used was 5 ng/ml shown with the corresponding percentage inhibition (mean ± 2 SE). At maximum inhibition, KK vs. KE/EE shows a significant difference (P = 0.015). Mean percentage inhibition observed for each genotype were as follows (% ± 2 SE): KK, 74.0 ± 6.7; KE, 83.2 ± 4.7; and EE, 90.5 ± 5.8.