Mutational analysis of the high affinity immunoglobulin E receptor β subunit gene in asthma

Background-The gene for the beta subunit of the high affinity receptor for immunoglobulin E (Fc epsilon RI-beta) on chromosome 11q13 is linked with clinical asthma and certain mutations have been identified. A study was undertaken to identify DNA variation in the Fc epsilon RI-beta gene in a population sample in which linkage between 11q13 and asthma was explained by bronchial hyperreactivity (BHR) but not atopy. Methods-DNA samples from 71 subjects with asthma, atopy, or BHR were analysed. The complete coding region, some of the introns, and some of the 5' untranscribed region of the Fc epsilon RI-beta gene were sequenced. Results-In the subjects studied there were no deviations from the published sequence in any of the seven coding exons of the Fc epsilon RI-beta gene. In particular, the three previously reported mutations (Ile181, Leu183, Glu237) were not detected. Two new polymorphisms were discovered, one at position 243 in the 5' untranscribed region and one at position 4390 in intron III. Neither of these variants showed significant association with asthma, atopy, or BHR. Conclusions-These results suggest that, in the population studied, linkage of asthma and BHR to 11q13 is not explained by mutations in the Fc epsilon RI-beta gene. Other mutations in the non-coding region of this gene or in adjacent genes must explain the linkage findings in this study.