BACKGROUND: Increased erythrocyte sodium-lithium countertransport (SLC) has been observed in patients with essential hypertension. An analytic strategy for identification of genetic variation contributing to hypertension is the evaluation of appropriate intermediate phenotypes for hypertension, such as SLC. Thus, in this study, genome-wide linkage scans for SLC were performed in two independent samples of pedigrees from the Rochester Family Heart Study (RFHS).METHODS: Genome-wide linkage scans for SLC were performed in independent samples of 232 and 252 non-Hispanic white families from the RFHS. Multipoint variance-component linkage analysis was performed using MERLIN.RESULTS: Chromosomes 8, 9, 10, 19, and 20 contained evidence for linkage (log of the odds [LOD] > or =2) in at least one sample of RFHS pedigrees. Consistent evidence of linkage for SLC between the two samples was observed on chromosome 10 (LOD = 2.02 at 64 cM in the first sample and LOD = 2.27 at 55 cM in the second sample).CONCLUSIONS: Consistent evidence of linkage (LOD > or =2) for SLC was observed in two independent samples of non-Hispanic white families on chromosome 10. Concordance of linkage evidence between the two samples provides confidence that a region on chromosome 10 contains genetic variation influencing SLC, which may potentially influence susceptibility to hypertension.