Author(s): Mao XQ, Shirakawa T, Yoshikawa T, Yoshikawa K, Kawai M
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 inflammation of the skin. The gene for MCC is located within a cluster of genes for cellular proteases on chromosome 14q11.2. We aimed to identify variants of MCC and another gene within this complex, and assess whether there is a genetic association between variants of MCC and atopic disorders-particularly eczema. METHODS: We randomly selected 100 controls and recruited patients-100 in each group-with atopic asthma, non-atopic asthma, atopic rhinitis, and atopic eczema. PCR amplification was used to test genomic DNA for an association between allelic polymorphisms in MCC and a flanking gene (CGL1, for the cathepsin-G-like protein) on chromosome 14q11 and asthma, rhinitis, and eczema. FINDINGS: We found a significant association between a BstXI polymorphism in MCC and eczema (odds ratio 2.17 [95% CI 1.21-3.88], p = 0.009), but no association with atopic asthma, rhinitis, or non-atopic asthma. There was no association between an Mboll polymorphism in CGL1 and any of the atopic disorders. INTERPRETATION: These findings suggest that variants of MCC may be one source of genetic risk for eczema.