Autosomal genomewide linkage scan for coronary artery calcification loci.
Coronary artery calcification (CAC), quantified by electron beam computed tomography, provides a measure of extent of coronary atherosclerosis in asymptomatic and symptomatic individuals. It is well recognized that coronary artery disease and CAC are complex processes that are influenced by many genetic and environmental factors. Several aspects of CAC quantity make genetic studies of it particularly challenging. These include the non-normality of CAC frequency distributions and the strong age- and sex-dependence of CAC levels. To search for regions that may contain genes influencing CAC quantity, a genome-wide scan was conducted on a sample enriched for hypertension from the Epidemiology of Coronary Artery Calcification Study. The genome-wide linkage scan was based on 370 anonymous markers spanning the 22 autosomal chromosomes in 29 families. The analysis sample consisted of 20 affected sib-pairs, 8 affected sib-trios and 1 family with 6 affected siblings. Here, affection status was defined as being above the 70th sex- and age-specific percentile based on a reference population. Mode-of-inheritance-free qualitative linkage analysis was used to analyze sib-pair data. Maximum multipoint lod scores were calculated using the computer software Genehunter-2. Weighted analyses were conducted using Holmans “possible triangle” constraint. The overall maximum lod scores were observed on chromosomes 6 (lod=2.22) and 10 (lod=3.24). Additional lod scores greater than 1.0 were observed on chromosomes 2, 14, 15 and 17. These results identify regions that may harbor genes involved in high sex- and age-specific levels of CAC (supported by HL46292).