Quantitative trait locus on Chromosome 19 for circulating levels of intercellular adhesion molecule-1 in Mexican Americans

Circulating soluble intercellular adhesion molecule-1 (sICAM-1) is a biochemical marker of inflammation. We performed variance-components-based quantitative genetic analyses in SOLAR of sICAM-1 in 1170 individuals from Mexican American families in the San Antonio Family Heart Study. The trait is heritable (h2 = 0.50 ± 0.06, P < 10−6). Multipoint linkage analysis using a 10-cM microsatellite map revealed a region on Chromosome 19p near marker D19S586 showing strong evidence of linkage for sICAM-1 (empirically adjusted univariate-equivalent LOD = 4.95), coincident with the structural gene ICAM1. This region has been identified previously as a QTL for inflammatory, autoimmune, and metabolic syndrome traits. There is significant evidence (P = 0.0023) of locus heterogeneity for sICAM-1 in this sample: a subset of pedigrees contributes most of the linkage signal for sICAM-1 on Chromosome 19, suggesting a logical focus for future genetic dissection of the trait.