Nonparametric linkage regression. I: Combined Caucasian CSGA and German genome scans for asthma

In this paper we applied the nonparametric linkage (NPL) regression approach to the combined Caucasian genome scan data from the Collaborative Study on the Genetics of Asthma (CSGA) and German family studies to search for regions of the genome that exhibit evidence for linkage to putative asthma-predisposing genes. The multipoint single-locus model identified three regions of the genome with LOD scores of approximately two or greater. These regions were on 6p near D6S291 (LOD = 2.78), 2p near D2S2298 (LOD = 2.11), and 1p near D1S1597 (LOD = 1.92). Modeling multiple loci together and testing for interactions among loci yielded stronger evidence for linkage in these regions. We observed a potential epistatic interaction between 2p and 14p (p = 0.0003) and conditional LOD scores of 2.75 on 1p, 3.89 on 6p, 1.64 on 7p, and 1.64 on 15q.