ASSOCIATION BETWEEN GENETIC-VARIANTS OF MAST-CELL CHYMASE AND ECZEMA

Background Atopy is a common syndrome underlying asthma, rhinitis, and eczema, and is characterised by high immunoglobulin E (IgE) responses to common antigens. IgE and mast-cell chymase (MCC-a serine protease secreted by skin mast cells) have a key role in atopic or allergic inf lammation of the skin. The gene for MCC is located within a cluster of genes for cellular proteases on chromosome 14q11.2. We aimed to ident ify variants of MCC and another gene within this complex, and assess w hether there is a genetic association between variants of MCC and atop ic disorders-particularly eczema. Methods We randomly selected 100 con trols and recruited patients-100 in each group-with atopic asthma, non atopic asthma, atopic rhinitis, and atopic eczema. PCR amplification w as used to test genomic DNA for an association between allelic polymor phisms in MCC and a flanking gene (CGL1, for the cathepsin-G-like prot ein) on chromosome 14q11 and asthma, rhinitis, and eczema. Findings We found a significant association between a BstXI polymorphism in MCC a nd eczema (odds ratio 2.17 [95% CI 1.21-3.88], p=0.009), but no associ ation with atopic asthma, rhinitis, or non-atopic asthma. There was no association between an Mboll polymorphism in CGL1 and any of the atop ic disorders. Interpretation These findings suggest that variants of M CC may be one source of genetic risk for eczema.