Quantitative trait loci for blood pressure exist near the IGF-1, the Liddle syndrome, the angiotensin II-receptor gene and the renin loci in man

Blood pressure (BP) is heritable and finding quantitative trait loci that i nfluence BP is an important step in identifying genes responsible for BP re gulation. Sixty-six pairs of dizygotic (DZ) twin subjects and their parents were used in a sib-pair analysis to look for linkage of selected candidate genes to the quantitative trait BP. Microsatellite markers were tested in the vicinity of the gene loci for insulin-like growth factor-1 (IGF-1), Lid dle syndrome, autosomal-dominant hypertension with brachydactyly, angiotens inogen, angiotensin II type I receptor, angiotensin-converting enzyme, reni n, and lipoprotein lipase. BP was measured in a standardized manner. Heart size was determined echocardiographically. Significant linkage was found at the IGF-1, Liddle syndrome, and AT(1) receptor gene for systolic BP. Linka ge for diastolic BP was found at the autosomal-dominant hypertension with b rachydactyly locus. Both systolic and diastolic BP were linked to the renin gene locus. The linkage was most consistent for the IGF-1 gene locus and s ystolic Bg. Linkage was also found between the IGF-1 gene locus and posteri or cardiac wall thickness, septal thickness, and left ventricular mass inde x. It is suggested that these quantitative trait loci may be important for the subsequent detection of allelic variants for elevated BP. Furthermore, these results linking the IGF-1 gene locus to both BP and cardiac dimension s underscore the importance of the IGF-1 gene as a candidate gene for cardi ovascular disease.