Quantitative Trait Locus on 15q for a Metabolic Syndrome Variable Derived from Factor Analysis

The metabolic syndrome represents a cluster of cardiovascular risk factors co‐occurring in the same individual. The aim of this study was to identify chromosomal regions encoding genes predisposing to the metabolic syndrome using composite factors derived from maximum likelihood‐based factor analysis. Genetic data were obtained from the Quebec Family Study and included 707 subjects from 264 nuclear families. Factor analyses were performed on eight metabolic syndrome‐related phenotypes including waist circumference; BMI; systolic and diastolic blood pressure; and plasma insulin, glucose, triglyceride, and high‐density lipoprotein‐cholesterol levels. Three factors were identified and interpreted as general metabolic syndrome, blood pressure, and blood lipids, respectively. The general metabolic syndrome factor had high factor loadings (>0.4) for all phenotypes and explained 42% of the total variance, and family membership accounted for 45.6% of the factor variance. A genome‐wide linkage scan performed with this first factor revealed the existence of a quantitative trait locus on chromosome 15 (86 cM) with a logarithm of odds score of 3.15. Suggestive evidence of linkage (logarithm of odds > 1.75) was also observed on chromosomes 1p, 3p, 3q, 6q, 7p, 19q, and 21q. These quantitative trait loci may harbor genes contributing to the clustering of the metabolic syndrome‐related phenotypes.