Clinical & Experimental Allergy

Lack of linkage between chromosome 5q23–33 markers and IgE/bronchial hyperreactivity in 67 Scottish families

Authors


H Mansur Molecular Medicine Unit, Level 6, Clinical Sciences Building, St. James's University Hospital, Leeds, LS9 7TF, UK.

Abstract

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.

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