Non-alcoholic fatty liver disease (NAFLD) is a spectrum of conditions marked by fatty infiltration of the liver (steatosis) and sometimes histologic evidence of inflammation (steatohepatitis) without a history of excessive alcohol ingestion. NAFLD is common and is strongly associated with obesity, insulin resistance (IR), and T2DM, three conditions with strong evidence for genetic pathogenesis; however, the genetic epidemiology of NAFLD is not well characterized. The central hypothesis of the proposed research is that NAFLD, for any given degree of adiposity, is highly familial and that genetic variations can explain not only difference in risk and severity of hepatic steatosis but also risk of T2DM between individuals. To test this hypothesis, we propose the following specific aims: (1) characterize the distribution of NAFLD using non-contrast electron beam computed tomography in a cohort of 1,000 participants of the Amish Family Calcification Study [AFCS]; 2) estimate the relative contributions of genes and measured environmental risk factors markers of NAFLD; 3) evaluate familial clustering among obesity, IR, NAFLD, T2DM and to determine the extent to which common genetic factors influence variation in these traits jointly (i.e. pleiotropy), (4) perform a genome-wide linkage analyses of markers of NAFLD and T2DM in the AFCS, (5) perform genetic association analyses of markers of NAFLD and T2DM and single nucleotide polymorphisms from candidate genes in chromosome regions identified by linkage analysis in AFCS and a subgroup of individuals from the Action for Health in Diabetes (Look AHEAD) Study. The proposed research builds on Dr. Kao's focus on the genetic epidemiology of obesity and T2DM. She will be assisted by mentors with expertise in medicine, epidemiology, statistics and molecular genetics. The new methods and expertise acquired as a result of this Career Development Award will equip Dr. Kao with the tools necessary to launch a fully independent career in genetic epidemiological research. This proposal is strengthened by: focus on a novel diabetes-related endophenotype; large sample of highly-informative families for linkage analyses (AFCS); availability of confirmed unrelated NAFLD cases for association analyses (Look AHEAD), assessment of a multitude of cardiovascular and environmental risk factors; state-of-the-art imaging of the liver; and comprehensive genetic analyses, including both genome-wide and candidate gene approaches. A deeper understanding of the molecular pathogenesis of obesity, IR, NAFLD, and T2DM may suggest new approaches for the prevention and treatment of these conditions.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Scientist Development Award - Research & Training (K01)
Project #
5K01DK067207-04
Application #
7367883
Study Section
Diabetes, Endocrinology and Metabolic Diseases B Subcommittee (DDK)
Program Officer
Hyde, James F
Project Start
2005-03-15
Project End
2010-02-28
Budget Start
2008-03-01
Budget End
2009-02-28
Support Year
4
Fiscal Year
2008
Total Cost
$128,958
Indirect Cost
Name
Johns Hopkins University
Department
Public Health & Prev Medicine
Type
Schools of Public Health
DUNS #
001910777
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Holliday, Elizabeth G; Traylor, Matthew; Malik, Rainer et al. (2014) Polygenic overlap between kidney function and large artery atherosclerotic stroke. Stroke 45:3508-13
Scialla, Julia J; Kao, W H Linda; Crainiceanu, Ciprian et al. (2014) Biomarkers of vascular calcification and mortality in patients with ESRD. Clin J Am Soc Nephrol 9:745-55
Cheng, Ching-Yu; Reich, David; Haiman, Christopher A et al. (2012) African ancestry and its correlation to type 2 diabetes in African Americans: a genetic admixture analysis in three U.S. population cohorts. PLoS One 7:e32840
Maruthur, Nisa M; Kao, W H Linda; Clark, Jeanne M et al. (2011) Does genetic ancestry explain higher values of glycated hemoglobin in African Americans? Diabetes 60:2434-8
Deo, Rahul C; Wilson, James G; Xing, Chao et al. (2011) Single-nucleotide polymorphisms in LPA explain most of the ancestry-specific variation in Lp(a) levels in African Americans. PLoS One 6:e14581
Scialla, Julia J; Plantinga, Laura C; Kao, W H Linda et al. (2011) Soluble P-selectin levels are associated with cardiovascular mortality and sudden cardiac death in male dialysis patients. Am J Nephrol 33:224-30
Hernaez, Ruben; Yeung, Edwina; Clark, Jeanne M et al. (2011) Hemochromatosis gene and nonalcoholic fatty liver disease: a systematic review and meta-analysis. J Hepatol 55:1079-85
Speliotes, Elizabeth K; Yerges-Armstrong, Laura M; Wu, Jun et al. (2011) Genome-wide association analysis identifies variants associated with nonalcoholic fatty liver disease that have distinct effects on metabolic traits. PLoS Genet 7:e1001324
Yeung, Edwina H; Saudek, Christopher D; Jahren, A Hope et al. (2010) Evaluation of a novel isotope biomarker for dietary consumption of sweets. Am J Epidemiol 172:1045-52
Estrella, Michelle M; Sperati, Chistopher J; Kao, Wen H L et al. (2010) Genetic epidemiology of chronic kidney disease. Curr Opin Nephrol Hypertens 19:283-91

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