Heritability and Genetic Correlations of Metabolic Disease-Related Phenotypes in Mexico: Preliminary Report from the GEMM Family Study

Abstract

Cardiovascular disease (CVD) is a major cause of mortality in the Republic of Mexico, and metabolic syndrome, a complex of CVD risk factors, is increasingly prevalent. To date, however, there have been few studies of the genetic epidemiology of metabolic syndrome in Mexico. As a first step in implementing the GEMM Family Study, a large, multicenter collaborative study, we recruited 375 individuals in 21 extended families, without ascertainment on disease, at 9 medical institutions across Mexico. Participants were measured for anthropometric (stature, weight, waist circumference) and hemodynamic (blood pressure, heart rate) phenotypes; glucose, cholesterol, and triglyceride levels were measured in fasting blood. Variance components-based quantitative genetic analyses were performed using SOLAR. All phenotypes except diastolic blood pressure were significantly heritable. Consistent with the definition of metabolic syndrome, many phenotypes exhibited significant environmental correlation, and significant genetic correlations were found between measures of adiposity and fasting glucose and fasting triglyceride levels. These preliminary data represent the first heritability estimates for many of these phenotypes in the Republic of Mexico and indicate that this study design offers excellent power for future gene discovery relative to metabolic disease.

A statistical investigation into the sharing of common genetic factors between blood pressure and obesity phenotypes in nuclear families from the Greater Bilbao (Spain)

“…This lack of correlation could be due to changes in the expression of genes during the growth process, affecting, therefore, covariation with BP phenotypes. However, our results are consistent with those observed in other adult populations such as the Mexican and Indians [7,14] in which no shared genetic effects were found between BP and these obesity traits. In summary, the reasons for the divergent results remain unclear and the absence of genetic correlations for some pairs of factors could be explained by the effect of age or by different genetic backgrounds among populations or by the sum of both.…”

“…The most commonly reported adiposity measures in relation to BP phenotypes include weight, waist circumference, skinfolds thickness and indices such as BMI and waist-to-hip ratio (WHR) [7][8][9][10][11][12][13][14]. Factors extracted from a factor analysis could represent features that contain a higher degree of genetic variance than the original variables separately [15].…”

Heritability and genetic correlations of obesity-related phenotypes among Roma people

“…Consequently, the complex and unique structure of these Roma people pedigrees seems to provide valid and robust information about the genetic and environmental contribution to variation in obesity-related traits. Our data are in agreement with previous studies, where heritability of obesity-related phenotypes were estimated in Indians (Mathias et al 2009;Zabaneh et al 2009), Western Eurasians (Hasselbalch et al 2008;Poveda et al 2010;Jelenkovic et al 2011), Mexicans (Bastarrachea et al 2007) and Arabs (Bayoumi et al 2007). The results of this study are also comparable to those reported in other overweight populations such as Samoans (Choh et al 2001) and Mexican Americans (Comuzzie et al 1994).…”

“…Pleiotropy was also found for an elevated number of pairs. The phenotypic, genetic and environmental correlations estimated from the present study are mostly in line with previous studies (Choh et al 2001;Schousboe et al 2004;Bastarrachea et al 2007;Hasselbalch et al 2008;Mathias et al 2009). The high phenotypic, genetic and environmental correlation for BMI-SF reported in the present study, which is in agreement with the studies of Hasselbalch et al (2008) and Schousboe et al (2004), indicate that variation in body mass is highly associated with variation in adiposity.…”

Lifestyle changes in descendants of parents with diabetes type 2

“…(10) . Although we neither had an adequate sample nor a broad design of nuclear families to assess the genetic component (which decreases the study's statistical power), it seemed interesting to us to assess the h 2 of insulin resistance (IR) among parents with DMT2 and their descendants, in order to estimate the environmental contribution…”