Our Staff
All our professionals at Gastroenterology of San Marcos maintain the highest level of accreditation and pursue ongoing education to stay abreast of the latest trends in gastroenterology.

Gastroenterology of San Marcos is the home of outstanding physicians, excellent nurses, and caring staff. Our main goal is to ensure our patients receive the highest quality of care in a professional and comfortable environment. The Central Texas Ambulatory Endoscopy Center continues to maintain three-year AAAHC certifications (the longest allowable) and received a perfect reviews in 2004, 2007, and 2010. We have been at the forefront of the industry for years now, and have already been using electronic health records for the past 3 years. We continue to employ the most technologically advanced equipment and cutting-edge procedures to bring our patients state-of-the-art care and achieve the best outcomes possible.
Our physicians are recognized both locally and throughout the region as some of the top authorities in the field. Dr. Kern Deschner has been appointed to the Texas Board of Medical Examiners as a subspecialty reviewer in the field of Gastroenterology. Dr. Coles serves on the board of Christus Santa Rosa Out Patient Surgery Center and the CSR Advisory Hospital Board. Our physicians continue to be named among the "Top Doctors" in the state for nearly a decade.
What makes us different? To see more about why to choose us, click here
Edward F. Coles, MD, FACP, FACG
W. Kern Deschner, MD
Dr. William Kern Deschner graduated Magna Cum Laude with a degree in Marine Biology from Texas A&M University. In 1979, he chose to pursue a degree in medicine from Baylor College of Medicine. He was an exceedingly gifted student, gaining membership into the Alpha Omega Alpha Medical Honor Society in addition to receiving Honors in Basic Sciences. Dr. Deschner graduated with honors in 1983, completed his internship and residency at Baylor Affiliated Hospital in 1986, and began his fellowship in Gastroenterology at Georgetown University Hospital in Washington D.C. During this time, he served as Clinical Instructor of Medicine/ Gastroenterology and, in 1988, he received the prestigious Lawlor Award for Best
Scientific Paper from the American College of Gastroenterology. In 1989, he accepted a position as Assistant Professor in the Department of Internal Medicine Division of Gastroenterology at the University of Texas Medical Branch. He then moved to San Marcos where he entered into a private practice of Gastroenterology.
Dr. Deschner is board certified in Internal Medicine and Gastroenterology. He has served as Director of Endoscopy and Chairman of the Department of Medicine at Central Texas Medical Center. In addition, he has held numerous other leadership positions including: President of the Tri-County Medical Society, Texas Medical Association House of Delegates, and member of the Board of Advisors for the Texas Society for Gastroenterology and Endoscopy.
Dr. Deschner and his wife Rhonda have been married since 1983. They have four children, Austin, Michelle, Mark, and Ethan. He is an involved member of Cypress Creek Church, serves as Scoutmaster for Troop 1907, and is a contributing author to the Newsletter of Lone Star Bonsai Federation. A devoted father, husband, and physician, he remains passionate about his profession and dedicated to providing the highest quality of care.
Thomas Kepczyk, MD, FACP, FACG
Dr. Thomas Kepczyk excelled in his undergraduate work at Arizona State University. In 1982, he graduated Summa Cum Laude with a BA in Chemistry and went on to pursue a degree in medicine from the University of Arizona. During his academic career, he proved to be a brilliant scholar and received numerous awards and memberships into coveted societies including: Alpha Omega Alpha Medical Honor Society, Phi Beta Kappa, and Phi Beta Phi. After graduating Summa Cum Laude from medical school in 1986, he moved to Texas to complete his internship and residency in Internal Medicine at Brooke Army Medical Center. In 1989, Dr. Kepczyk was selected as the “Outstanding Resident in Ambulatory Care” at BAMC. He gained further experience at the 67th Evacuation Hospital in Wuerzburg where he served as a Staff Internist and then Chief of Medicine. In July of 1991, he returned to Brooke Army Medical Center to complete his fellowship in Gastroenterology, and then, in 1993, he accepted a position as a staff gastroenterologist at Fitzsimons Army Medical Center in Colorado. During this time, he accepted the position of Clinical Instructor in the Department of Medicine at the University of Colorado. In 1995, he moved back to Texas and entered into private practice at Gastroenterology of San Marcos and New Braunfels.
Dr. Kepczyk is board certified in Internal Medicine and Gastroenterology. He serves as an active member on the board of the Central Texas Ambulatory Endoscopy Center and on the board of McKenna Ambulatory Surgical Center. He is a Fellow in the American College of Physicians as well as the American College of Gastroenterology and remains a part of other professional organizations including the American College of Gastrointestinal Endoscopy. In addition, he is a member of the Primary Care Committee and serves as Director of Nutrition at Central Texas Medical Center.
Dr. Kepczyk was born in Berlin, Germany, moved to the United States with his family at age 5, and now calls Texas home. He and his wife Barbara have 2 sons, Alexander and Nicholas. He remains a devoted father and husband, serves as an active member in his community and church, truly loves his profession and takes pride in providing the utmost in quality of care.
Shannon J. Marek, MD
Dr. Marek was born and raised in Texas, growing up working in his family’s automotive business outside of Dallas. As a first generation college student, Dr. Marek attended Baylor University on Presidential scholarship. While there he excelled in the advance coursework involved with the Interdisciplinary Core, participated in the Honors program, and served in the Baylor Chamber of Commerce. He graduated cum laude with a Bachelors of Arts degree in Psychology. He then went on to receive his Doctorate of Medicine from the University of Texas at Houston Medical School. His internal medicine internship and residency was then at the University of Alabama at Birmingham, one of the top 10 internal medicine programs in the nation. While there, he received multiple awards, including a peer elected award naming him one of the top overall residents. Thereafter, the combination of intellectual challenge and procedural technique led him to training in Gastroenterology at the Medical College of Georgia. He has presented at multiple national conferences, and helped to author a preeminent textbook in the field of GI.
Dr. Marek has trained in numerous aspects of advanced endoscopy, including EGD, Colonoscopy, and ERCP. He has extensive training in luminal stent placement, endoscopic mucosal resection, and wireless capsule endoscopy. He is also trained in hemorrhoid banding using the CRH O’regan system; the most advanced, pain free method of nonsurgical hemorrhoidal treatment. Dr. Marek maintains a commitment to ensure the latest advancements in therapy are available for the benefit of his patients. He is board certified in both Internal Medicine and Gastroenterology.
In 2001, Dr. Marek had the privilege of marrying his beautiful wife Shanan. They have 3 children, Cole, Mason, and Grant with a golden retriever named Jake. Their family is actively involved in Oakwood Baptist Church in New Braunfels, TX. When not at work; spending time with family, friends, and church activities are top priorities. He enjoys all things outdoors including hunting, fishing, hiking, biking, and even the occasional sprint triathlon. As a physician with humble beginnings and a loving family to keep him grounded, Dr. Marek strives to translate the complex medical world into an understandable experience for his patients.
Carlos A. Neghme, MD
Dr. Carlos A. Neghme excelled in the Undergraduate Honors Program at Loyola University in Chicago, Illinois. In 1987, he graduated Cum Laude with a Bachelor’s degree in Science. He was then accepted into the College of Medicine at the University of Illinois and received his Doctorate of Medicine in 1991. He remained in Chicago to continue his medical training. He completed his residency in Internal Medicine at the University of Loyola Medical Center and, in 1996, specialized in the field of Gastroenterology. During his time at Loyola University, Dr. Neghme became proficient in endoscopic procedures and in clinical evaluation of patients. Under the guidance of highly respected and well-known professors, he trained with the most advanced endoscopic equipment. As an expert in the field, he is remarkably skilled in Upper Endoscopy, Colonoscopy, and Biliary Endoscopy procedures. He has participated in research analyzing Colon Cancer and Polyp Prevention, Ulcerative Colitis, and Hepatitis C.
Dr. Neghme is originally from Chicago, Illinois but has made Texas his home. He has been practicing in the field of Gastroenterology for over a decade and is now an esteemed partner at Gastroenterology of San Marcos and New Braunfels. He has a true passion for his profession and each patient is ensured the utmost in quality of care.
