A genomewide search for quantitative-trait loci underlying asthma

A genomewide screen for quantitative-trait loci (QTLs) that underlie asthma was performed on 533 Chinese families with asthma, by the unified Haseman- Elston method. Nine asthma-related phenotypes were studied, including force d expiratory volume in 1 s (FEV1), forced vital capacity (FVC), airway resp onsiveness as indicated by methacholine (MTCH)-challenge test, serum total immunoglobulin E (TIgE), serum-specific immunoglobulin E, eosinophil count in peripheral blood, and skin-prick tests with three different allergens (c ockroach, Dermatophagoides pteronyssinus, and D. farinae). Our study showed significant linkage between airway responsiveness to MTCH and D2S1780 on c hromosome 2 (P<.00002) and provided suggestive evidence (P<.002) for six ad ditional possible QTLs: D10S1435 and D22S685, for FEV1; D16S412, for FVC; D 19S433, for airway responsiveness to MTCH; D1S518, for TIgE; and D4S1647, f or skin reactivity to cockroach. No significant or suggestive evidence of l inkage for the other four traits was found.