Lack of linkage between chromosome 5q23-33 markers and IgE/bronchial hyperreactivity in 67 Scottish families.
BACKGROUND
Raised serum immunoglobulin E (IgE) and bronchial hyperreactivity (BHR) are risk factors for the expression of the asthma phenotype. Previous studies have reported evidence for linkage between these traits and markers on the 5q23-33 cytokine gene cluster.


OBJECTIVE
To test for linkage between total serum IgE/BHR and microsatellite markers which map to the 5q23-33 region in an ethnically distinct cohort of families from Aberdeen, Scotland.


METHODS
We performed a linkage study between five polymorphic markers (spanning the chromosome 5q23-33 region) and total serum IgE and BHR traits. A cohort of 67 families, who were recruited originally to study the natural history of wheeze, were clinically characterized and genotyped for D5S404, IL4, IRF-1, IL9, D5S436 markers. Linkage analyses were performed using the nonparametric Haseman-Elston algorithm for the quantitative trait log IgE, and the nonparametric LOD score (NPL-score) of the GENEHUNTER package for the qualitative traits serum IgE and BHR.


RESULTS
The results of the nonparametric linkage analysis using either the Haseman-Elston algorithm or NPL-score were consistent and showed no evidence for linkage with IgE. There was also no evidence for linkage between the BHR traits (at cut-off values of PD20FEV1 < 8 mmol and 16 mmol) and any of the tested five microsatellite markers.


CONCLUSIONS
This study presents evidence against the presence of a gene with a major effect on total serum IgE or BHR in the 5q23-33 region, in this ethnic group.
Mansur
A H
AH
Molecular Medicine Unit, Clinical Sciences Building, St. James's University Hospital, Leeds, LS9 7TF, UK.
Christie
G
G
Turner
A
A
Bishop
D T
DT
Markham
A F
AF
Helms
P
P
Morrison
J F
JF
D000293:Adolescent; D016535:Bronchial Hyperreactivity / Q000235:genetics* / Q000276:immunology; D002648:Child; D002895:Chromosomes, Human, Pair 5 / Q000235:genetics*; D017931:DNA Primers / Q000737:chemistry; D004276:DNA, Satellite / Q000032:analysis; D004268:DNA-Binding Proteins / Q000235:genetics; D008040:Genetic Linkage; D005819:Genetic Markers; D005838:Genotype; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood*; D050856:Interferon Regulatory Factor-1; D007371:Interferon-gamma / Q000235:genetics; D015847:Interleukin-4 / Q000235:genetics; D016906:Interleukin-9 / Q000235:genetics; D008126:Lod Score; D010375:Pedigree; D010750:Phosphoproteins / Q000235:genetics; D016133:Polymerase Chain Reaction; D012606:Scotland
D017931:DNA Primers; D004276:DNA, Satellite; D004268:DNA-Binding Proteins; D005819:Genetic Markers; C494257:IRF1 protein, human; D050856:Interferon Regulatory Factor-1; D016906:Interleukin-9; D010750:Phosphoproteins; D015847:Interleukin-4; D007073:Immunoglobulin E; D007371:Interferon-gamma