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

BACKGROUND The gene for the β subunit of the high affinity receptor for immunoglobulin E (FcεRI-β) on chromosome 11q13 is linked with clinical asthma and certain mutations have been identified. A study was undertaken to identify DNA variation in the FcεRI-β 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 FcεRI-β 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 FcεRI-β 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 FcεRI-β gene. Other mutations in the non-coding region of this gene or in adjacent genes must explain the linkage findings in this study.