Atopy, a common familial syndrome underlying allergic asthma and rhinitis, is characterised by sustained immunoglobulin E (IgE) responses to common allergens. We have previously shown genetic linkage of atopy to the chromosome 11q13 marker D11S97 (pms51) through maternally derived alleles, but no likely candidate genes were known to lie near this marker. We have analysed maternally derived alleles from 155 sibling-pairs affected by atopy to seek evidence of linkage between the gene predisposing to atopy and other markers on chromosome 11q13. We found that the beta subunit of the high-affinity receptor for IgE (Fc epsilon RI-beta) also lies on chromosome 11q13, and that it is in close genetic linkage with the gene for atopy. The known roles of Fc epsilon RI in antigen-induced mast-cell degranulation and in the release of cytokines that enhance IgE production make the gene for its beta subunit a candidate for the chromosome 11 atopy locus.