Heritabilities of the metabolic syndrome and its components in the Northern Manhattan Family Study

Abstract

Aims/hypothesis: Growing evidence suggests that the traits comprising the metabolic syndrome have a genetic basis. However, studies of genetic contributions to the syndrome are sparse. Against this background, we sought to estimate the heritability of the metabolic syndrome and its component traits. Materials and methods: We investigated 803 subjects from 89 Caribbean-Hispanic families who have enrolled to date in the current Northern Manhattan Family Study and for whom metabolic syndrome information was available. Metabolic syndrome was defined in accordance with the National Cholesterol Education Program Adult Treatment Panel III (NCEP/ATPIII) criteria. Variance component methods were used to estimate age and sex-adjusted heritability of the metabolic syndrome and its components. To obtain the structures underlying the metabolic syndrome, we performed principal component factor analyses using six quantitative phenotypes included in the ATPIII definition. Results: The heritability for the metabolic syndrome was 24% (p=0.009), and ranged from 16 to 60% for its five components. Factor analysis yielded two independent factors (factor 1: lipids/glucose/obesity; factor 2: blood pressure). Heritability analysis revealed significant genetic effects on both factors (44% for lipids/glucose/obesity, and 20% for blood pressure). Conclusions/interpretation: In the Caribbean-Hispanic families investigated, we demonstrated moderate and significant heritabilities for the metabolic syndrome itself, as well as for individual components and independent factors of the syndrome. These results provide evidence that could support future tasks of mapping susceptibility loci for this syndrome.

Are there common genetic and environmental factors behind the endophenotypes associated with the metabolic syndrome?

“…These results indicate that phenotypic variation in individual endophenotypes is mostly due to genetic effects and this is consistent with the many univariate analyses published by us and others [9][10][11][12][13]23]. Environmental factors contributing to the variation of the endophenotypes between individuals appear to be mostly experienced by individuals and not shared between family members.…”

“…A wide range of heritabilities (mostly moderate to high) have been estimated for obesity traits (mean: 0.55; range: 0.37-0.80) [9][10][11][12][13][14]; insulin-related traits (mean: 0.38; range: 0.08-0.75) [9][10][11][13][14][15][16]; BP (mean: 0.41; range: 0.16-0.76) [9][10][11][12][13] and lipid traits (mean: 0.46; range: 0.20-0.70) [9][10][11][12][13]. However, the underlying mechanism of the clustering of these characteristics in an individual remains unclear [17].…”

Association between polymorphisms in the Clock gene, obesity and the metabolic syndrome in man

“…27 The present study further supports a role for genetic factors in the familial clustering of the metabolic syndrome and its component and related traits.…”

USF1 gene variants contribute to metabolic traits in men in a longitudinal 32-year follow-up study

“…The molecular background of the syndrome remains unknown but the individual traits characterising the condition are strongly hereditary, and several studies have reported clustering of these traits [25,26]. In our study the prevalence of metabolic syndrome was alarmingly high (41.9%).…”