Esteban González Burchard received his M.D. degree from Stanford University School of Medicine in 1995. He completed clinical training in Internal Medicine at Harvard's Brigham and Women's Hospital and Pulmonary/Critical Care Medicine training at UCSF. Dr. González Burchard also completed clinical research training at the Harvard School of Public Health. He received his M.P.H. degree in epidemiology from UC Berkeley. He joined the UCSF faculty in 2001. Dr. González Burchard's major academic interest centers on identifying genetic and environmental risk factors for asthma and drug response (pharmacogenetics) in ethnically diverse populations. In addition, Dr. González Burchard directs the UCSF DNA Bank.

Research Interests
Asthma varies widely among different racial and ethnic groups. In the U.S., asthma prevalence, morbidity and mortality are highest in Puerto Ricans, intermediate in Dominicans and Cubans, and lowest in Mexicans and Central Americans. Socioeconomic and environmental differences do not fully explain this observation. One potential explanation is that there may be gene-environment interactions which can differentially modify risk for asthma in different racial/ethnic groups. On a global level, these gene-environment interactions can be tested using genetic ancestry as a surrogate for genetic risk factors. Although the relative ancestral contributions to the contemporary Latino gene pool make each Latino national group unique, there is substantial overlap in ancestry. Therefore, individuals with similar ancestral proportions may still belong to different Latino subgroups. Furthermore, most Latinos are unaware of their precise ancestry and report their ancestry based on the national origin of their family and their physical appearance. The unavailability of precise ancestry and the genetic complexity among Latinos may complicate asthma research studies in this population. On the other hand, precisely because of this complexity, Latinos present a unique opportunity to disentangle the clinical, social, environmental, and genetic underpinnings of population differences in asthma prevalence, severity and bronchodilator drug responsiveness.

My research interests center on determining why there are significant disparities in asthma prevalence, asthma severity and even lower drug responsiveness to common asthma medications among racial/ethnic populations in the U.S. Specifically, my research focuses on elucidating the complex interaction of social, genetic and environmental factors and their impact on asthma and asthma-related traits. To this end, we initiated the Genetics of Asthma in Latino Americans (GALA) Study, which was designed to compare genetic, environmental and clinical characteristics between Puerto Rican and Mexican asthmatics.

The GALA Study is an ongoing multicenter international collaborative effort, designed to identify and directly compare clinical and genetic risk factors associated with asthma and asthma severity among Puerto Ricans and Mexicans. Puerto Rican and Mexican asthmatic subjects were recruited from four clinical centers located in San Francisco, New York City, Puerto Rico and Mexico City.  We are using a family based approach (Transmission/Disequilibrium Test or TDT) to identify genetic variants among asthma candidate genes. Identified variants are analyzed using the TDT to determine whether these alleles are associated with asthma, asthma severity and drug responsiveness among these populations. In addition, we initiated SAGE (Study of African Americans, Asthma, Genes & Environments). The goal of SAGE is to identify ethnic specific, pharmacogenetic, and asthma associated genetic risk factors among African Americans.

Finally, I am part of the Study Of PHarmacogenetics In Ethnically diverse populations (SOPHIE) Study. The goal of the SOPHIE Study is to examine ethnic-specific genetic variation and its role in drug response. The SOPHIE project has established a local cohort of 1000 healthy volunteers recruited from four stringently defined racial groups (Chinese, African American, Mexican, and Caucasian) in the San Francisco area. This cohort is distinctive in that volunteers are willing to take part in future pharmacokinetic and pharmacogenetic studies to determine if genotype-phenotype interactions exist.

Recent Publications
*Choudhry, S, *González Burchard, E, Borrell, LN, Tang, H, Gomez, I, Naqvi, M, Nazario, S, Torres, A, Casal, J, Martinez-Cruzado, JC, Ziv, E, Avila, PC, Rodriguez-Cintron, W, and Risch, NJ. Ancestry-Environment Interactions and Asthma Risk among Puerto Ricans. Am J Resp Crit Care Med, July 2006, in press. *These authors contributed equally to this manuscript.

Tsai HJ, Kho JY, Shaikh N, Kho JY, Battle N, Naqvi M, Navarro D, Matallana H, Lilly CM, Eng C, Kumar G, Thyne S, Watson HG, Meade K, Le Noir M, Choudhry S, González Burchard E, from the Study of African American, Asthma, Genes and Environments (SAGE). Beta-2 Adrenergic receptor polymorphisms: Pharmacogenetic response to bronchodilator among African American asthmatics. Hum Genet. 2006 Jan; 118(5):626-39.

Tsai YJ, Choudhry, S, Kho, J, Beckman, K, Tsai, HJ, Navarro, D, Matallana H, Castro, RA, Lilly, CM, Nazario, S, Rodriguez-Santana, JR, Casal, J, Torres, A, Salas, J, Chapela, R, Watson, HG, Meade, K, Avila, PC, Rodriguez-Cintron, W, LeNoir, M, and González Burchard, E, on behalf of the GALA and SAGE Investigators. The PTGDR Gene is not Associated with Asthma in Three Ethnically Diverse Populations. J Allergy and Clinical Immunology, in press, July 2006.

Ziv, E, John, EM, Choudhry, S, Kho, J, Lorizio, W, Perez-Stable, EJ, González Burchard, E.  Genetic ancestry and Risk Factors for Breast Cancer Among Latinas in the San Francisco Bay Area. Cancer Epidemiology Biomarkers and Prevention; Sept 2006, in press.

Peralta, CA, Ziv, E, Katz, R, Reiner, A, González Burchard, E, Fried, L, Kwok, PY, Psaty, B, Shlipak, M. African ancestry, socioeconomic status and kidney function in elderly African Americans:  a genetic admixture analysis. Journal of American Society of Nephrology, Sept 2006, in press.

Tsai HJ, Kho JY, Shaikh N, Choudhry S, Naqvi M, Navarro D, Matallana H, Castro R, Lilly CM, Watson HG, Meade K, Le Noir M, Thyne S, Ziv E, González Burchard E, from the Study of African American, Asthma, Genes and Environments (SAGE). Admixture-Matched Case-Control Study: A Practical Approach for Genetic Association Studies in Admixed Populations. Hum Genet 2006 Jan; 118(5):626-39. Nov 2005.

Choudhry S, Ung N, Avila PC, Ziv E, Nazario S, Casal, J Torres A, Gorman JD, Salari K, Rodriguez-Santana JR, Toscano M, Senter-Sylvia J, Alioto ME, Salazar M, Gomez I, Fagan JK, Salas J, Clark S, Lilly C, Matallana H, Selman M, Chapela R, Sheppard D, Weiss ST, Ford JG, Boushey HA, Drazen JM, Rodriguez-Cintron W, Silverman EK and Burchard EG from the Genetics of Asthma in Latino Americans (GALA) Study. Pharmacogenetic Differences in Response to Bronchodilators Between Puerto Rican and Mexican Asthmatics. AJRCCM May 5, 2005.

Pawlikowska L, Tran MN, Achrol AS, Ha C, Burchard E, Choudhry S, Zaroff J, Lawton MT, Castro R, McCulloch CE, Marchuk D, Kwok PY, Young WL; UCSF BAVM Study Project. Polymorphisms in transforming growth factor-beta-related genes ALK1 and ENG are associated with sporadic brain arteriovenous malformations. Stroke 2005 Oct; 36(10):2278-80. Epub 2005 Sep 22.

González Burchard, E, Borrell, LN, Choudhry, S, Naqvi, M, Tsai, HJ, Rodriguez-Santana, JR, Chapela, R, Rogers, SD, Mei, R, Rodriguez-Cintron, W, Arena, JF, Kittles, R, Perez-Stable, EJ, Ziv, E and Risch N. Latino Populations: A unique opportunity for the study of Race, Genetics and Social Environment in Epidemiologic Research. Am J Public Health 2005 Dec; 95(12):2161-8. Epub 2005 Oct 27.

Choudhry S, Coyle, NE, Lind, D, Tang, H, Salari, K, Clark SL, Ung, N, Matallana, H, Avila, PC, Nazario, S, Casal J, Torres, A, Toscano, M, Castro, R, Rodriguez-Cintron, W, Shriver, MD, Kwok, Sheppard, D, Pui-Yan, Risch, N, Ziv, E and Burchard, EG.  Population stratification confounds genetic association studies among Latinos. Hum Genet 2006 Jan; 118(5):652-64. Epub 2005 Nov 8.

Tsai HJ, Choudhry S, Naqvi M, Rodriguez-Cintron W, Burchard EG and Ziv E. Comparison of three statistical methods to estimate genetic ancestry and control for stratification in genetic association studies among admixed populations. Hum Genet 2005 Oct 6; 1-10.

Choudhry, S, Avila, PC, Nazario, S, Ung, N, Rodriguez-Santana, JR, Casal, J, Tsai HJ, Torres, A, Ziv, E, Toscano, M, Senter-Sylvia, J, Alioto, ME, Salazar, M, Gomez I, Fagan, JK, Salas, J, Lilly, C, Matallana, Castro R, H, Selman, M, Sheppard, D, Weiss, ST, Ford, JG, Drazen, JM, Rodriguez-Cintron, W, Chapela, R, Silverman, EK and Burchard, EG from the Genetics of Asthma in Latino Americans (GALA) Study. Gene-Environment Interaction between CD14 Gene and Tobacco Smoke Exposure Influence Asthma Severity and IgE Levels in Mexican and Puerto Rican Asthmatics. Am J Resp Crit Care Med July 15, 2005.

Reiner AP, Ziv E, Lind DL, Nievergelt CM, Schork NJ, Cummings SR, Phong A, Burchard EG, Harris TB, Psaty BM, Kwok PY. Population Structure, Admixture, and Aging-Related Phenotypes in African American Adults: The Cardiovascular Health Study. Am J Hum Genet. 2005 Jan 19;76(3).

Salari K, Choudhry S, Lind D, Tang H, Clark SL, Ung N, Matallana H, Avila PC, Nazario, S Casal J, Torres A, Toscano M, Castro R, Rodriguez-Cintron W, Shriver MD, Kwok PY, Sheppard D, Risch N, Ziv E and Burchard, EG.  Individual Ancestry is Associated with Asthma Severity from the Genetics of Asthma in Latino Americans (GALA) Study.  Journal of Genetic Epidemiology Nov 2004.

Burchard EG, Avila PC, Nazario S, Casal J, Torres A, Rodriguez-Santana JR, Toscano M, Senter-Sylvia J, Alioto ME, Salazar M, Gomez I, Fagan JK, Salas J, Lilly C, Matallana H, Ziv E, Castro R, Selman M, Chapela R, Sheppard D, Weiss ST, Ford JG, Boushey HA, Rodriguez-Cintron W, Drazen JM and Silverman EK, from the Genetics of Asthma in Latino Americans (GALA) Study. Lower Bronchodilator Responsiveness in Puerto Rican than in Mexican Asthmatic Subjects. AJRCCM e-pub Nov 14, 2003.

Lind DL, Choudhry S, Ziv E, Ung N, Salari K, Coyle NE, Nazario S, Casal J, Torres T, Avila PC, Salas J, Selman M, Weiss ST, Ford JF, Boushey HA, Drazen JM, Silverman EK, Chapela R, Rodriguez-Cintron W, Sheppard D, Kwok PY and Burchard, EG. Sequence Variants in the ADAM33 are not associated with asthma in Mexican Americans or Puerto Rican Americans from the Genetics of Asthma in Latino Americans (GALA) Study. AJRCCM e-pub Sept 4, 2003.

Ziv E and Burchard EG. Human Population Structure and Genetic Association Studies. Pharmacogenomics. 2003 Jul;4(4):431-41

Burchard EG, Ziv E, Coyle N, Lin-Gomez S, Tang H, Karter AJ, Mountain J, Perez-Stable EJ, Sheppard D, Risch N. The Importance of Race and Ethnic Background in Biomedical Research and Clinical Practice. New England Journal of Medicine 2003; 348(12): 1077-1192.

Risch N, Burchard EG, Ziv E, Tang H. Classification of Humans in Biomedical Research: Genes, Race and Disease. Genome Biology 2002 3(7): 1-2007.

Burchard EG, Silverman EK, Rosenwasser LJ, Borrish L, Yandava C, Pillari A, Weiss ST, Lilly CM, Ford J, Hasday J, Drazen JM. Association Between a Sequence Variant in the IL-4 Gene Promoter and FEV1 in Asthma. AJRCCM 1999; 160:919-922.

Wu C, Kurbegov D, Lattin B, Burchard E, Finkle C, Valantine H, Billingham M, Starnes V, and Clayberger C. Cytokine Gene Expression in Human Cardiac Allograft Recipients. Transplant Immunology: September 1994, 2(3): 199-207.

Whitehead B, Stoeher C, Wu C, Patterson G, Burchard E, Theodore J, Clayberger C, and Starnes V. Cytokine Gene Expression in Human Lung Transplant Recipients. Transplantation 56: 956-961, 1993.