Genetic epidemiology and genome-wide linkage analysis of carotid artery ultrasound traits in multigenerational African ancestry families.

ABSTRACT

OBJECTIVE: Intima-media thickness, adventitial diameter and lumen diameter are indicators of cardiovascular disease risk. The influence of genetic factors on these measures in African ancestry populations is not well defined. Therefore, we estimated heritability and performed genome-wide linkage analysis of carotid ultrasound traits in 7 multigenerational families of African ancestry. METHODS: A total of 395 individuals (7 pedigrees; mean family size = 56; 2392 relative pairs) aged ≥18 years had a common carotid artery ultrasound scan. Statistical analyses were conducted using pedigree-based maximum likelihood methods. RESULTS: Significant covariates included age, sex, body mass index or height and waist, and systolic blood pressure. Residual heritabilities ranged from 0.35 ± 0.10 to 0.64 ± 0.12 (P < 0.0001). We identified a novel quantitative trait locus for adventitial and lumen diameters on chromosome 11 (max LOD = 4.09, 133 cm). CONCLUSION: Further fine mapping of this region may identify specific mutations predisposing to subclinical vascular disease among African ancestry individuals.