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Student Profiles:
Sandy An

Sandy An, MD, PhD



Matriculated: 2007

Graduate Program: Biochemistry

Education:

BSPH (Biostatistics), 2007, University of North Carolina, Chapel Hill, NC
BA (Chemistry), 2007, University of North Carolina, Chapel Hill, NC
MD/PhD, Wake Forest University, Winston Salem, NC

Residency:
Anesthesiology - Vanderbilt University, Nashville, TN

Research:
Diabetes is a major public health problem currently affecting over 24 million individuals in the United States. Type 2 diabetes (T2D) is the main culprit, making up 90-95% of all diabetes cases. A major contributor to the diabetes phenomenon is recent obesity epidemic. As a result, understanding the impact of obesity on diabetes has become an increasingly important area of study. Adipose tissue was previously thought to be an inert tissue, serving as a site for energy storage. However, more recent studies have shown that adipose tissue is an active endocrine organ, secreting a wide variety of adipocytokines, including adiponectin. Adiponectin is a widely studied adipocytokine that has been implicated in glucose, lipid and energy homeostasis. Adiponectin has been found to be inversely correlated with obesity, insulin resistance and diabetes.

The goal of our study is to explore the genetic variation attributing to plasma adiponectin levels. Plasma adiponectin levels are highly heritable, with heritabilities ranging between 40-70%. Previous studies have suggested the ADIPOQ locus itself is the major genetic determinant of plasma adiponectin levels. Common variations in the ADIPOQ gene, however, have accounted for less than 10% of the observed variance in adiponectin levels. Previously, we identified a low frequency (1.1%) coding variant, G45R, in Hispanic Americans from the Insulin Resistance Atherosclerosis Family Study (IRASFS) which accounted for an estimated 16.7% of the proportion of variance in plasma adiponectin levels in the Hispanic population. The current study was designed to quantify the variation in adiponectin attributable to clinical traits, low frequency variants, and common variants in ADIPOQ, in a Hispanic sample. Additionally, we are studying the contribution of genetic variants in ADIPOQ to diabetes status, a clinical trait that has been widely reported to be associated with adiponectin variation in an African American population.

advisor: Dr. Don Bowden

Presentations:
Oral Presentations
An S, Palmer ND, Brown WM, Haffner SM, Norris JM, Rotter JI, Guo X, Chen I, Wagenknecht LE, Bowden DW. Family-Based Identification of a Rare Adiponectin Gene Variant in Hispanic American (HA) Families from the IRAS Family Study. Diabetes 59 suppl 1: 2010, A36.


Poster presentations
Marchant B, An S, Tong C. A patient with severe asthma and moderate aortic insufficiency from bicuspid valve for laparoscopic inguinal hernia surgery. Abstract for Poster Presentation. American Society of Anesthesiology. 2013

An S, Palmer N, Freedman B, Rotter J, Ng M, Chen I, Norris J, Wagenknecht L, Langefeld C, Bowden D. Analysis of Low Frequency Coding Variants in ADIPOQ Challenges Conventional Models of Adiponectin Action in Humans. Abstract for Poster Presentation. American Diabetes Association. 2012, 1542-P

Cox A, Lambird J, An S, Carr J, Freedman B, Bowden D. Is Adiponectin Signaling associated with subclinical cardiovascular disease in the Diabetes Heart Study? Abstract for poster presentation. International Symposium on Atherosclerosis, Sydney, Australia.

An S, Palmer N, Hanley A, Ziegler J, Brown W, Haffner S, Norris J, Rotter J, Guo X, Chen I, Wagenknecht L, Langefeld C, Bowden D. 2011 Genetic Architecture of Adiponectin in Hispanic Americans from the IRAS Family Study. Abstract for poster presentation. International Congress of Human Genetics, Montreal, Canada.

Cooke J, Ng M, Lu L, Li J, An S, Hester J, Xu J, Freedman B, Langefeld C, Bowden D, Palmer N. Genetic Risk Assessment of Type 2 Diabetes-Associated Polymorphisms in African Americans. Abstract for poster presentation. International Congress of Human Genetics, Montreal, Canada.

An S, Palmer N, Cooke J, Lu L, Divers J, Ng M, Langefeld C, Freedman B, Bowden D. 2011 Evaluation of European-derived Type 2 Diabetes loci in an African American population. Abstract for poster presentation. American Physician Scientist Association, Chicago, IL.

An S, Palmer N, Cooke J, Lu L, Divers J, Ng M, Langefeld C, Freedman B, Bowden D. 2010 Exploration of European-derived Type 2 Diabetes loci in an African American population. Abstract for poster presentation. American Society of Human Genetics, Washington D.C.

Palmer ND, McDonough CW, Hicks PJ, An SS, Hester JM, Cooke JN, Bostrom MA, Lu L, Ziegler JT, Sale MM, Shriner D, Adeyemo A, Rotimi C, Ng MCY, Langefeld CD, Freedman BI, Bowden DW. Identification of Novel Type 2 Diabetes Loci in African Americans using a Genome-wide Association Approach. Am. J. Hum. Genet. Program number 279, 2010

McDonough DW, Palmer ND, Bostrom MA, Hicks PJ, Roh BH, Wing MR, Cooke JN, Hester JM, An SS, Talbert ME, Lu L, Ng MCY, Divers J, Langefeld CD, Freedman BI, Bowden DW. A Genome Wide Association Study for Diabetic Nephropathy Genes in African Americans. Diabetes 59 suppl 1: 2010, A56

Palmer ND, McDonough CM, An SS, Hester JM, Cooke JN, Bostrom MA, Lu L, Ziegler JT, Sale MM, Divers J, Shriner D, Adeyemo A, Rotimi C, Freedman BI, Ng MCY, Langefeld CD, Bowden DW. Discovery of Novel African American Type 2 Diabetes Loci Using a Genome-wide Association Approach. Genomics of Common Disease 2010.

An S, Palmer N, Brown W, Haffner S, Norris J, Rotter J, Guo X, Chen I, Bowden D. 2010. Identification and Evaluation of a novel ADIPOQ Polymorphism in Hispanic-American (HA) families from the Insulin Resistance Atherosclerosis Family Study (IRASFS). Abstract for poster presentation. American Physician Scientist Association, Chicago, IL

Bowden DW, Palmer ND, An SS, Brown WM, Haffner SM, Norris JM, Rotter JI, Guo X, Chen YDI, Langefeld CD. Identification and evaluation of an ADIPOQ mutation in Hispanic American families from the Insulin Resistance Atherosclerosis Family Study. International Congress of Endocrinology 2010.


Institutional Abstracts
An S, 2011 The Genetic Architecture of Adiponectin in Hispanic Americans from the IRAS Family Study. Abstract for poster presentation. Wake Forest Department of Biochemistry Research Day, Winston-Salem, NC

An S, 2010 Family-based Identification of a Rare Adiponectin Gene Variant in Hispanic American families from the IRAS family study. Abstract for poster presentation. Wake Forest Department of Biochemistry Research Day, Winston-Salem, NC.

An S. 2009 Genetic Analysis of Adiponectin in a Hispanic American Population. Abstract for poster presentation. Wake Forest Department of Biochemistry Research Day, Winston-Salem, NC

An S, Fuchs K, Pielak G. 2007. Measuring Diffusion Inside Cells. UNC-CH Summer Undergraduate Research Foundation, Chapel Hill, NC. Oral Presentation.

An S, Palmer N, Cooke J, Lu L, Divers J, Ng M, Langefeld C, Freedman B, Bowden D. 2011 European Type 2 Diabetes (T2D) loci evaluated in an African American (AA) sample. Abstract for poster presentation. Wake Forest University Graduate Student Research Day, Winston-Salem, NC

An S. 2011 Family-based Identification of a Rare Adiponectin Gene Variant in Hispanic American (HA) families from the IRAS Family Study. Abstract for poster presentation. Wake Forest University Biochemistry Research Day, Winston-Salem, NC

An S, Palmer N, Ng M, Adeyemo A, Rotimi C, Freedman B, Bowden D. 2009. Comprehensive Genetic Evaluation of Variation at the TCF7L2 Locus in African Americans. Abstract for poster presentation. Wake Forest University Biochemistry Research Day, Winston-Salem, NC

An S, Ahmet M, Lyles D. 2009. VSV Interactions with Human Dendritic Cells. Abstract for poster presentation. Wake Forest University School of Medicine Medical Student Research Day, Winston-Salem, NC

An S, Palmer N, Bowden D. 2008. Associations of SNPs in TCF7L2 with Type II Diabetes in an African American Population. Abstract for poster presentation. Wake Forest University School of Medicine Medical Student Research Day, Winston-Salem, NC

Publications:
An S, Palmer N, Hanley A, Ziegler J, Brown W, Haffner S, Norris J, Rotter J, Guo X, Chen I, Wageknecht L, Langefeld C, Bowden D. Association between ADIPOQ SNPs with plasma adiponectin, glucose homeostasis and adiposity phenotypes in the IRAS Family Study. Mol Genet Metab. 2012 Dec;107(4):721-8. doi: 10.1016/j.ymgme.2012.10.003. Epub 2012 Oct 13.

An S, Palmer N, Hanley A, Ziegler J, Brown W, Haffner S, Norris J, Rotter J, Guo X, Chen I, Wageknecht L, Langefeld C, Bowden D. The Genetic Contributors to Adiponectin Variation in African Americans and Association with Type 2 Diabetes. Accepted at Obesity

An S, Palmer N, Hanley A, Ziegler J, Brown W, Haffner S, Norris J, Rotter J, Guo X, Chen I, Wagenknecht L, Langefeld C, Bowden D. Estimating the Contributions of Rare and Common Genetic Variations and Clinical Measures to a Model Trait: Adiponectin. Genet Epidemiol. 2013 Jan;37(1):13-24. doi: 10.1002/gepi.21685. Epub 2012 Oct 2

Cox A, Lambird J, An S, Register T, Carr J, Freedman B, Bowden D. Variants in adiponectin and adiponectin signaling pathway genes show little evidence of association with measures of subclinical CVD in the Diabetes Heart Study. 2011. DOI: 10.1002/oby.20184 Accepted at Obesity

Cooke J, Ng M, Palmer N, An S, Hester J, Freedman B, Langefeld C, Bowden D. Genetic Risk Assessment of Type 2 Diabetes Associated Polymorphisms in African Americans. Diabetes Care. 2012 Feb; 35:287-292.
Palmer N, McDonough C, Hicks P, Roh B, Wing M, An S, DIAGRAM Consortium, MAGIC Investigators, et al. A Genome-Wide Association Search for Type 2 Diabetes Genes in African Americans. PLoS One. 2012 Jan 7(1):e292002

Bowden D, An S, Palmer N, Brown W, Norris J, Haffner S, Guo X, Rotter J, Chen I, Wagenknecht L, Langefeld C. Molecular Basis of a Linkage Peak: Identification of a Rare Genetic Variant in the ADIPOQ Gene through Family-based Linkage Analysis in the IRAS Family Study. Hum Mol Genet. 2010 Oct. 19(20): 4112-20.

Palmer N, Hester J, An S, Adeyemo, Rotimi, Langefeld C, Freedman B, Ng CY, Bowden D. 2010. Resequencing and analysis of variation in the TCF7L2 gene in African Americans suggests that SNP rs7903146 is the causal diabetes susceptibility variant. Diabetes. 2011 Feb; 60(2): 662-8.

McDonough C, Palmer N, Bostrom M, Hicks P, Roh B, Wing M, Cooke J, Hester J, An S, Talbert M, Lewis J, Rudock M, Lu L, Ng CY, Sale M, Divers J, Langefeld C, Freedman B, Bowden D. 2011. A Genome Wide Association Study for Diabetic Nephropathy Genes in African Americans. Kidney Int. 2011 Mar; 79(5): 563-72.

Dissertation:
An SS (2012 March 9) Genetic Variants of ADIPOQ and Association with Plasma Adiponectin Levels, Type 2 Diabetes, Glucose Homeostasis and Adiposity. Doctoral Dissertation.

Honors and Awards:
2013 Pennell Pro Humanitate Vitae Fund Award for Global Health
2007-2014 MD/PhD Academic Merit Scholarship
2009-2010 Alumni Student Travel Award
2010-2014 Louis J. Argenta Scholar
2010-2014 NIDDK Ruth L. Kirschstein National Research Service Award F30

Professional Society Memberships:
American Society of Anesthesiology
American Physician Scientist Association
American Society of Human Genetics
National Society of Collegiate Scholars

Interests & Hobbies:
exercising, shopping, traveling, reading, playing outside

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