ABSTRACT
BACKGROUND: High blood pressure is a well established risk factor for morbidity and mortality acting through heart disease, stroke and cardiovascular disease. Genome wide scans have linked regions of nearly every human chromosome to blood pressure related traits. We have capitalized on beneficial qualities of the Old Order Amish of Lancaster, PA, a closed founder population with a relatively small number of founders, to perform a genome wide homozygosity by descent mapping scan. Each individual in the study has a non zero probability of consanguinity. Systolic and diastolic blood pressures are shown to have appreciable dominance variance components. RESULTS: Areas of two chromosomes were identified as suggestive of linkage to SBP and 5 areas to DBP in either the overall or sex specific analyses. The strongest evidence for linkage in the overall sample was to Chromosome 18q12 (LOD = 2.6 DBP). Sex specific analyses identified a linkage on Chromosome 4p12-14 (LOD in men only = 3.4 SBP). At Chromosome 2q32-33, an area where we previously reported significant evidence for linkage to DBP using a conventional identity by descent approach, the LOD was 1.4; however an appreciable sex effect was observed with men accounting for most of the linkage (LOD in men only = 2.6). CONCLUSION: These results add evidence to a sex specific genetic architecture to blood pressure related traits, particularly in regions of linkage on chromosome 2, 4 and 18.
Subject(s)
Chromosome Mapping , Genetic Predisposition to Disease , Homozygote , Hypertension/genetics , Sex Characteristics , Adolescent , Adult , Aged , Aged, 80 and over , Chromosomes, Human, Pair 2 , Chromosomes, Human, Pair 4 , Chromosomes, Human, Pair 8 , Female , Humans , Male , Middle Aged , PennsylvaniaABSTRACT
Serotonin has been implicated in common disorders involving the central nervous, gastrointestinal, cardiovascular, and pulmonary systems. We describe the first genome-wide screen to identify quantitative trait loci (QTLs) influencing whole blood serotonin in 567 members of a single large pedigree, using a novel association-based mapping approach. We identified an association between the beta3 integrin (ITGB3) Leu33Pro polymorphism on 17q21 and whole blood serotonin levels (P-value = 9.8 x 10(-5)). This variant explained the evidence for linkage in this region when included as a covariate in the linkage analysis (change in LOD from 1.87 to 0.16), indicating that ITGB3 may be an important serotonin QTL.
Subject(s)
Integrin beta3/genetics , Quantitative Trait Loci , Serotonin/blood , Female , Gene Frequency , Genetic Linkage , Humans , Lod Score , Male , Microsatellite Repeats , PedigreeABSTRACT
Serum triglyceride (TG) level is a well-known risk factor for cardiovascular disease, a leading cause of morbidity and mortality in Western countries. Although genome-wide scans for TG have been conducted in several populations, few loci have shown strong evidence for linkage. The Hutterites are a founder population, which practices a communal lifestyle that includes a uniformly high-fat, high-cholesterol diet. We measured serum TG in 485 Hutterites >or=14 years old and performed a genome-wide scan to find genetic determinants of the observed variation in TG levels, using mapping methods that take advantage of the extensive inbreeding and linkage disequilibrium (LD) in this single, 1623-member pedigree. We report two highly significant associations with TG levels, alleles at D2S410 on 2q14 (locus P=5.8 x 10(-6), genome-wide P=0.005) and at IFNA on chromosome 9p21 (locus P=4.3 x 10(-5), genome-wide P=0.024). In each case, homozygosity at the locus is associated with low TG levels, suggesting that alleles at nearby loci may protect against high TG levels.