Quantitative trait loci on chromosomes 3 and 17 influence phenotypes of the metabolic syndrome

TLDR

The metabolic syndrome, comprising glucose intolerance, dyslipidemia, high blood pressure, abdominal fat patterning, total body adiposity, and insulin resistance, is a strong predictor of obesity‑related morbidities and premature mortality, and candidate genes at epistatic QTLs may influence its two biological precursor pathways. The study aimed to identify major genetic loci influencing metabolic syndrome phenotypes. A genome‑wide scan was conducted with a 10‑centiMorgan map on 2,209 individuals from 507 nuclear Caucasian families. Linkage analysis revealed a QTL on chromosome 3 (3q27) linked to six metabolic traits (lod 2.4–3.5) that interacts epistatically with a QTL on chromosome 17 (17p12) linked to plasma leptin (lod 5.0).

Abstract

Recent research has emphasized the importance of the metabolic cluster, which includes glucose intolerance, dyslipidemia, and high blood pressure, as a strong predictor of the obesity-related morbidities and premature mortality. Fundamental to this association, commonly referred to as the metabolic syndrome, is the close interaction between abdominal fat patterning, total body adiposity, and insulin resistance. As the initial step in identifying major genetic loci influencing these phenotypes, we performed a genomewide scan by using a 10-centiMorgan map in 2,209 individuals distributed over 507 nuclear Caucasian families. Pedigree-based analysis using a variance components linkage model demonstrated a quantitative trait locus (QTL) on chromosome 3 (3q27) strongly linked to six traits representing these fundamental phenotypes [logarithm of odds (lod) scores ranged from 2.4 to 3.5]. This QTL exhibited possible epistatic interaction with a second QTL on chromosome 17 (17p12) strongly linked to plasma leptin levels (lod = 5.0). Situated at these epistatic QTLs are candidate genes likely to influence two biologic precursor pathways of the metabolic syndrome.