Heritability of Cardiovascular and Personality Traits in 6,148 Sardinians

Abstract

In family studies, phenotypic similarities between relatives yield information on the overall contribution of genes to trait variation. Large samples are important for these family studies, especially when comparing heritability between subgroups such as young and old, or males and females. We recruited a cohort of 6,148 participants, aged 14–102 y, from four clustered towns in Sardinia. The cohort includes 34,469 relative pairs. To extract genetic information, we implemented software for variance components heritability analysis, designed to handle large pedigrees, analyze multiple traits simultaneously, and model heterogeneity. Here, we report heritability analyses for 98 quantitative traits, focusing on facets of personality and cardiovascular function. We also summarize results of bivariate analyses for all pairs of traits and of heterogeneity analyses for each trait. We found a significant genetic component for every trait. On average, genetic effects explained 40% of the variance for 38 blood tests, 51% for five anthropometric measures, 25% for 20 measures of cardiovascular function, and 19% for 35 personality traits. Four traits showed significant evidence for an X-linked component. Bivariate analyses suggested overlapping genetic determinants for many traits, including multiple personality facets and several traits related to the metabolic syndrome; but we found no evidence for shared genetic determinants that might underlie the reported association of some personality traits and cardiovascular risk factors. Models allowing for heterogeneity suggested that, in this cohort, the genetic variance was typically larger in females and in younger individuals, but interesting exceptions were observed. For example, narrow heritability of blood pressure was approximately 26% in individuals more than 42 y old, but only approximately 8% in younger individuals. Despite the heterogeneity in effect sizes, the same loci appear to contribute to variance in young and old, and in males and females. In summary, we find significant evidence for heritability of many medically important traits, including cardiovascular function and personality. Evidence for heterogeneity by age and sex suggests that models allowing for these differences will be important in mapping quantitative traits.

Meta-analysis of telomere length in 19 713 subjects reveals high heritability, stronger maternal inheritance and a paternal age effect

“…Maximum likelihood analyses as implemented in POLY 41 were used to evaluate different models of familial resemblance and these analyses were based on all data (ie, allowing for more than 2 siblings per family). In these analyses, TL was adjusted for age, gender and batch by specifying these as fixed effects on TL.…”

Genetic contributions to circadian activity rhythm and sleep pattern phenotypes in pedigrees segregating for severe bipolar disorder

“…To guard against statistical artifacts induced by skewed distributions, before analyses we used, in SOLAR, a standard rank-based procedure (37) to inverse-normal transform all phenotypes and thereby avoid correlations between relatives or inflated heritability estimates (38).…”

The role of eosinophils and basophils in allergic diseases considering genetic findings

“…Eosinophils and basophils are known to be heritable traits with heritability estimate ranged from 14% for basophils to 30-35% for eosinophil counts [28,29]. To our knowledge, no association between genes and basophil counts or percent was investigated at a candidate level.…”