Chromosome 14q was screened for loci modulating immunoglobulin E (IgE) phenotypes in 15 extended and 45 nuclear asthmatic families using a panel of 14 microsatellite markers. We examined the reported linkage between the TCR A/D locus on 14q11.2 and specific (cognate) allergic responses and observed supportive evidence for linkage between a general skin prick test reactivity trait (but not with total serum IgE) and TCRA microsatellite (in the total sample of informative sib-pairs p = 0.039, in selected sample of one or zero affected parent p = 0.017). We also show suggestive evidence for a novel linkage between markers D14S75 and D14S63 on 14q13-23 and log total serum IgE (p = 0.034 and p = 0.0029). The evidence for linkage with marker D14S63 on 14q23 is strengthened by the finding of association of allele 165 to log IgE (p = 0.0029). We conclude that chromosome 14q may contain a locus close to TCR A/D at 14q11.2 linked to skin prick reactivity and a locus at 14q13- 23 linked to total serum IgE.