Submitted to: Obesity
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2006
Publication Date: 9/5/2006
Citation: Voruganti, S.V., Goring, H.H., Diego, V.P., Cai, G., Mehta, N., Haack, K., Cole, S.A., Butte, N., Comuzzie, A. 2006. Genome-wide scan for plasma ghrelin detects linkage on chromosome 1p36 in Hispanic children: Results from the Viva La Familia study [abstract]. Obesity. 14:A196. Interpretive Summary:
Technical Abstract: Disorders in energy homeostasis are believed to be among the key contributing factors in the development of obesity. The rapid increase in the prevalence of obesity, particularly in children, is a major public health issue. Ghrelin is a brain-gut peptide with an important role in the regulation of energy intake. The aim of this study was to investigate the genetic influence on plasma ghrelin and its relationship with adiposity-related phenotypes in children from the Viva La Familia study. Children (n = 1030) were selected from 319 Hispanic families. Anthropometric measurements and plasma levels of ghrelin were estimated according to standard procedures. Heritabilites, genetic correlations and chromosomal linkage were obtained using variance components method implemented in SOLAR program. Mean age, BMI and plasma ghrelin of these children were 11 +/- 4 years, 25 +/- 8 kg/m2 and 38 +/- 16 pg/ml, respectively. Univariate genetic analyses showed significant heritabilities (p < 0.001) for BMI, (h2 = 0.41), weight (h2 = 0.31), fat mass (h2 = 0.27), percent fat (h2 = 0.35), waist circumference (h2 = 0.41), waist to height ratio (h2 = 0.41) and plasma ghrelin (h2 = 0.60). Bivariate analyses of ghrelin with adiposity traits showed significant genetic correlations (p < 0.0001) with weight (rhog = -0.48), BMI (rhog = -0.53), fat mass (rhog = -0.50), percent fat (rhog = -0.45), waist circumference (rhog = - 0.54), and waist to height ratio (rhog = -0.52). A genome-wide scan for ghrelin detected significant linkage on chromosome 1p36.2, between STR markers D1S2697 and D1S2667 (LOD score = 3.2). Several family based studies have reported linkages for obesity-related phenotypes in the region of 1p36. Gene that encodes for mammalian Target of Rapamycin (mTOR) protein, also known as FRAP1, is located at 1p36.2. One of the several functions of mTOR is as a cellular fuel sensor in the regulation of food intake. Other candidate genes that are related to obesity and are located in this region are Phosphotidylinositol 3-kinase, catalytic, delta (PIK3CD), nuclear receptor subfamily 0, group b, member 2 (NR0B2). Thus, these results indicate the importance of this region in the regulation of food intake and energy homeostasis in Hispanic children from the Viva La Familia Study.