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History of Pediatric Gastroenterology & Nutrition at MassGeneral Hospital for Children

The Pediatric Gastroenterology Unit of what was known as the Children’s Service at Massachusetts General Hospital was established in 1972. The unit’s first director, Allan Walker, MD, trained in Pediatrics and Immunology at the University of Minnesota Hospitals under Robert Good, MD. Since no pediatric gastroenterology (GI) training programs existed in 1969, Dr. Walker left pediatrics for three years to train as an adult GI fellow with Dr. Kurt Isselbacher on the Medical Service at Mass General. 

Once established, the nascent Pediatric GI Unit received substantial impetus by aligning itself with the well-established and nationally recognized GI Unit of the Medical Services at Mass General. Pediatric GI fellows could take rotations in medical GI, attend and participate in weekly GI Grand Rounds and journal clubs as well as the weekly research conference. Since Pediatric GI had no NIH training grant at its beginning, Dr. Isselbacher graciously allowed the Pediatric GI fellows to be funded on his training grant during their two year period of research fellowship.

This close working relationship with Adult GI has continued to be a major strength of the Pediatric GI program at MassGeneral Hospital for Children and has led to many collaborations in both basic and clinical research over the years, most recently with the support of Dr. Daniel Podolsky, who followed Dr. Isselbacher as Chief of the GI Unit at Mass General and Dr. Ramnik Xavier, who has followed Dr. Podolsky. Since GI subspecialty patients frequently require ongoing care beyond the cut off period of 21 years for pediatrics, it is helpful to have transitional care by both pediatric and medical gastroenterologists until the patient adjusts to a new situation. This is done seamlessly and provides outstanding continuity of patient care at Mass General.

Over the next 10 years after its inception, the pediatric unit flourished. Pediatricians in training became aware of the potential of gastroenterology as a subspecialty and Pediatric Department chairmen recognized the expanding field required more expertise than that provided by the General Academic Pediatrician. In addition, specialized procedures (liver biopsy, endoscopy, pH probes, etc.) became part of the practice of gastroenterology and could only be done by specially trained pediatric gastroenterologists. With the recognition that many gastrointestinal and hepatic conditions occurred in the pediatric age period and were more complex than conditions encountered in adult GI medicine, many pediatricians, interested in the pathophysiology of disease, were attracted to choose pediatric gastroenterology as a subspecialty.

Accordingly, the Pediatric GI Unit at Mass General, because of the reputation of gastroenterology at the hospital and because of the emphasis on a physician/scientist approach to the subspecialty, attracted outstanding applicants wishing to enter the field as academic subspecialists.

Beginning in 1972, two pediatricians from various training programs in the United States and elsewhere were accepted into the program. These trainees entered a three-year training program consisting of one year of clinical rotations in Pediatric Gastroenterology followed by two years of laboratory research in an established laboratory of investigation that could enhance the fellows’ research expertise in related areas of interest. From the beginning, the overall theme of research under Dr. Walker’s supervision was developmental mucosal immunology, work that continues to this day.

In 1981, with the departure of Richard Grand, MD, from Children’s Hospital to direct Pediatric GI at Tufts New England Medical Center/Floating Children’s Hospital, Dr. Walker was asked by Mary Ellen Avery, MD, Chairman of Pediatrics at Children’s Hospital, and Donald Medearis, MD, Chairman of the Children’s Service at Mass General, to establish a Combined Program in Pediatric Gastroenterology at the two pediatric services at Harvard.

From 1981 until 2001, a Combined Program in Pediatric Gastroenterology existed. In this program, four to five fellows per year were accepted for a three-year period of clinical and research training.

In 1990, the first Pediatric Gastroenterology subspecialty board examination was held to certify pediatric gastroenterologists as boarded subspecialists. This required three years of clinical and research training, which included a continuity clinic to follow patients during the two research years. A committee of faculty (within and outside of Pediatric GI) was established to monitor the progress of the fellows during their research experience.

During the early 1990’s, Harvard established a Clinical Effectiveness Program as a partnership between its hospitals and the Harvard School of Public Health to train fellows of various subspecialties in clinical research. This program occurred in parallel within the two years of fellowship by clinically-oriented fellows and could result, if the fellow so desired and took subsequent classes, in a Masters of Science Degree from the Harvard School of Public Health. This program expanded the options for GI fellows and in some cases junior faculty to do either bench or clinical research as part of their fellowship.

The years of combined fellowship in Pediatric GI at Harvard allowed for an expanded faculty development. Ronald Kleinman, MD, one of Dr. Walker’s earliest fellows, became the Division Chief of the program at Mass General. A major renovation of the joint endoscopy suite allowed for expanded procedural options in both pediatric and adult gastroenterology. In addition, an active Liver Transplant Service was added, which broadened the Pediatric GI referral base. Mass General combined with the Brigham and Women’s Hospital to form Partner’s Health Care, which increased the referral base for pediatric patients, thus expanding the Pediatric GI services.

In 2001, Dr. Walker stepped down from his role as Chief of the Combined Program in Pediatric Gastroenterology to return to Mass General to expand the research facilities. He obtained 15,000 square feet of research space and expanded the Pediatric GI capacity to include eight Principal Investigators, 15 research fellows, (including two Pediatric GI fellows doing basic research) and several graduate students in Building 149 and Building 114 in the Charlestown Navy Yard (an expanded off campus research facility for Mass General).

From its inception as a Pediatric Unit to the establishment of a combined program and then two separate programs again in Pediatric GI (occurring in 2005), more than 100 Pediatric GI fellows have been trained in the Mass General program. Many of these fellows have established their own program in Pediatric Gastroenterology at medical schools throughout the United States, the UK, Europe, Australia and Asia. Almost 50 percent of trainees are still actively involved in clinical or basic research and more than 80 percent practice at academic centers.

Program Accreditation

The Harvard Medical School Program in Pediatric Gastroenterology & Nutrition at MassGeneral Hospital for Children was accredited by the Accreditation Council for Graduate Medical Education (ACGME) as an independent program in July 2006. The program provides three years of progressive educational experience, which includes the development of procedural skills, responsibility for patient care, and participation in research that meets the program requirements of the ACGME and board eligibility in pediatric gastroenterology by the ABP for trainees completing the program.

Program Overview

The Pediatric Gastroenterology & Nutrition Division at MassGeneral Hospital for Children is a large, broad-based consultative service providing expertise in gastrointestinal, liver, pancreatic and nutritional disorders in infants, children and adolescents. Massachusetts General Hospital is a world leader in research and treatment of liver and gastrointestinal disorders and offers close collaboration between the pediatric and adult programs for patient care, and joint efforts in clinical and basic science research.

A number of centers of excellence exist within the Pediatric Gastroenterology & Nutrition Division at MassGeneral Hospital for Children, including:

  • Center for Celiac Research & Treatment- is dedicated to improving the quality of life for patients with celiac disease, while learning the cause of the disease and finding a cure.
  • Center for Diagnostic, Therapeutic and Interventional Endoscopy- provides both diagnostic and interventional procedures in a state-of-the-art pediatric endoscopy unit.
  • Center for Nutrition- focuses on a multidisciplinary approach to treat children with nutritional issues, in particular feeding difficulties and overweight or obesity. The programs integrate state-of-the-art resources with compassionate and comprehensive care.
  • Center for Inflammatory Bowel Disease- provides multidisciplinary clinical care for the most challenging pediatric patients with inflammatory bowel disease. Through population studies, the center is engaged in clinical, translational and basic science studies in the immunological and the genetic basis of the disease.
  • Food Allergy Center- provides unified multidisciplinary consultation among specialists in Pediatric Gastroenterology, Pulmonary, Psychology, as well as adult and pediatric allergists. This multispecialty collaboration facilitates outstanding clinical and basic science research opportunities.
  • Liver Transplantation- an integral part of the Mass General Transplant Program, it provides coordinated, multidisciplinary long-term care to pediatric patients before and after organ transplantation.
  • Neurogastroenterology Program- provides a multidisciplinary team approach aimed at restoring nutritional status and improving bowel function in children with a variety of congenital or acquired intestinal problems
  • Airway, Voice and Swallowing Center for Children- combines the expertise of multiple medical sub-specialties, including Pediatric Otolaryngology, Gastroenterology and Pulmonology in the coordinated assessment and management of children with disorders involving the airway and swallowing.
  • Center for Pediatric Hepatobiliary and Pancreatic Disease- provides clinical care for infants and children with liver disease and supports a very active teaching and research effort.
  • Lurie Center for Autism- is a multidisciplinary program designed to evaluate and treat children, adolescents and adults with a wide variety of conditions including autism and autism spectrum disorders, Asperger syndrome and developmental delays. It is the clinical arm of the Lurie Center for Autism, which also has research, advocacy and training programs.
  • Pediatric Weight Center- provides advanced, comprehensive, multidisciplinary care for both children and adults. Also an NIH funded, clinical and basic research center.

The overall goals and objectives of the fellowship program in Pediatric Gastroenterology & Nutrition are to fully train pediatricians to become expert, board certified consultants in Pediatric Gastroenterology, Hepatology and Nutrition in an academic setting and to have the capacity to become independent basic scientists or clinical investigators.

The clinical training entails developing competency in all procedures, including investigative and interventional endoscopy, pH and impedance probe use and interpretation, and the performance and interpretation of motility studies. At the completion of their training, fellows must have a comprehensive knowledge of the field and have the ability to present data in an oral and written manner and have a complete understanding of the scientific method.


The Division of Pediatric GI and Nutrition meets weekly for an educational conference. Approximately one half of the conferences are designated for Journal Club. Two members of the Pediatric GI Division, either faculty or fellow, present a major manuscript in detail selected from assigned journals. The articles are chosen based on the relevance of the data and conclusions to clinical practice and basic understanding of the pathophysiology of disease. Thus, each month the most important papers published in a list of 10 journals are presented in the conference. Once each month, (except July and August) the Journal Club conference is combined with the Mucosal Immunology Laboratory during which a clinical research and a basic science article in a related topic are presented for discussion. Once each month a quality improvement (QI) conference is held. Usually, first year fellows identify potential cases for discussion and after consultation with the program director two or three cases that illustrate areas for quality improvement are selected for presentation. This may involve discussion of when a direct admission to the hospital is appropriate or should first be assessed through the Emergency Department or, proper equipment failure reporting in the Endoscopy Unit.

The weekly Pediatric GI Core Conference provides an opportunity for fellows to learn fundamental normal and pathologic physiology as well as standard of care practices in pediatric gastroenterology and nutrition. The topics of the lecture series are considered in a two year cycle, with some lectures presented every year and some learning objectives addressed every two years. The topics of the lecture series are based on the guidelines of the Program Requirements for Fellowship Education in Pediatric Gastroenterology (ACGME, July 1, 2009) and requests by the fellows.

All fellows and faculty are strongly encouraged to attend and participate in the weekly Pediatric Grand Rounds, Adult GI Grand Rounds and the Pediatric Anesthesia/Surgery Conference.

Teaching Opportunities

Fellows have active teaching roles with residents and medical students during inpatient rounds. Fellows may also choose to participate in formal resident education by being a lecturer on a selected topic for the resident noon conference or in a less formal way by participating in discussions during the daily resident morning report.

Fellow Exchange Program

Dr. Allan Walker, Director of the Mucosal Immunology Laboratory, Massachusetts General Hospital and Dr. Ian R. Sanderson, Professor of Pediatric Gastroenterology, Barts and The London School of Medicine and Dentistry, Queen Mary Hospital, University of London have developed an exchange program in which, every year, a senior fellow from each program is invited to spend a month or more with the other training program. This has been an outstanding opportunity for visiting fellows to observe and experience different clinical practices, visit collaborating research laboratories, and attend conferences that would not otherwise be possible.

Affiliated Programs


Our fellowship program accepts applicants with U.S. citizenship or ECFMG certified J1 visas without bias towards visa status. There must be a minimum of three years remaining on the applicant’s visa in order to complete fellowship training. Our institutional Graduate Medical Education and ACGME accreditation requirements specify that all applicants must be board eligible/certified in pediatrics as determined by the American Board of Pediatrics.


Dr. Gary Russell completed his pediatric residency and gastroenterology fellowship training at Riley Children’s Hospital, Indiana University. He moved to Boston to pursue research in the burgeoning field of mucosal immunology. His academic interests include inflammatory bowel disease, eosinophilic esophagitis and medical education. Dr. Russell became the program director of the HMS Program in Pediatric Gastroenterology and Nutrition at MGHfC in 2008 and takes seriously his responsibility in helping guide the careers of the next generation of pediatric gastroenterologists. Outside of his academic responsibilities he enjoys being the medical co-director of the CCFA Camp Oasis, New York.

Dr. Kriston Ganguli left her home state of Minnesota to pursue her pediatric residency training in Boston. She was interested in pursuing fellowship training and was equally attracted to a career in pediatric gastroenterology and neonatology. She ultimately completed her fellowship training in pediatric gastroenterology at MassGeneral Hospital for Children, during which her research interest was founded. She was fortunate to join the MGHfC staff and currently balances clinical responsibilities with her basic science research career, investigating the use of secreted bacterial anti-inflammatory factors in reducing intestinal inflammation in preterm infants. Additionally, Dr. Ganguli is an Associate Director of the pediatric gastroenterology fellowship training program, Director of the MGHfC pediatric gastroenterology resident elective and the Physician Champion of the Quality Improvement Team within the division. Outside of her professional activities, she spends busy evenings and weekends with her husband and three active sons.

Dr. Christopher Moran has been a life-long resident of Massachusetts, completing his undergraduate work at Boston College and his medical school training at Tufts University. After completing residency at MassGeneral Hospital for Children, he began his Pediatric GI fellowship at MGHfC and focused his research on studying inflammatory bowel disease (IBD). His current research is focused on the genetics of very early onset IBD (VEO-IBD). Dr. Moran is an Associate Director of the Pediatric Gastroenterology Fellowship Program and a Co-Director of the Pediatric Gastroenterology Infusion Unit. He and his wife spend their free time with their two young children, teaching them about the folklore of the Boston Red Sox.

Research Experience

First-year fellows are exposed to a wide variety of potential research experiences through personal interactions with the pediatric GI faculty as well as faculty throughout the Mass General and Harvard Medical School system during conferences and other opportunities. First-year fellows meet with the program director to discuss their interests in clinical/basic science research and meet with investigators within the division as well as throughout the institution to help formulate plans for a research experience during their second and third years of fellowship. When a fellow decides on a research project and a research mentor, a scholastic oversight committee (SOC) is formed to oversee the research project and the progress achieved. The chairperson of the SOC is the pediatric GI faculty advisor for the fellow and is responsible for compiling a summary report of each SOC meeting, held once or twice yearly, that is submitted to the program director.

The research laboratories have regular meetings to review research progress, which the fellows are expected to attend and participate in. Additionally, fellows are strongly encouraged to supplement their experience with formal courses (basic science, statistics, study design and methodologies) at Mass General, Harvard and MIT. For those research fellows desiring an extended in-depth research experience, additional protected time (minimum of 50 percent) as a junior faculty member is encouraged through application for various career awards such as Clinical Investigator Award (CIA) or the Physician Scientist Award (PSA) at the National Institutes of Health The goal of this comprehensive program is to train an independent Pediatric Gastroenterology & Nutrition consultant capable of achieving independent grant-supported funding with either clinical or basic research interests for a faculty position at a medical school in the United States or elsewhere.

Although multiple research opportunities are available to fellows within the division of pediatric gastroenterology and the Mucosal Immunology Laboratory, each fellow is encouraged to explore other research opportunities within Harvard University and MIT.

Research Opportunities

  • Allan Goldstein Lab- My laboratory is interested in the development of the enteric nervous system (ENS), a complex neuronal network whose principal function is to maintain normal intestinal motility.
  • Harvard Catalyst- Harvard Catalyst brings together the intellectual force, technologies, and clinical expertise of Harvard University and its affiliates and partners to reduce the burden of human illness.
  • The Laboratory for Tissue Engineering and Organ Fabrication- The Laboratory for Tissue Engineering and Organ Fabrication is designing and building replacement living tissues and organs to ultimately translate to clinical therapies.
  • Lurie Center for Autism Research - The mission of the Lurie Center for Autism is to advance knowledge of the causes of and treatments for autism spectrum disorders and other developmental disorders and rapidly translate these discoveries into exceptional clinical care over a lifetime.
  • Mucosal Immunology Laboratory- The major mission of the Mucosal Immunology and Developmental Gastroenterology Laboratories remains a multidisciplinary approach to characterize the role of the enterocyte in mucosal barrier function at the interface between microbial luminal stimuli and lymphoid effector responses.
  • Pediatric Hepatobiliary & Pancreatic Program- The Pediatric Hepatobiliary & Pancreatic Program at MassGeneral Hospital for Children diagnoses and treats infants, children and adolescents with diverse hepatic, biliary and pancreatic disorders.
  • Pediatric Weight Center- The pediatric weight program at the Massachusetts General Hospital Weight Center provides comprehensive evaluation and care for children and adolescents who are overweight or obese.
  • Shreffler Laboratory- The Shreffler Laboratory is interested in the mechanisms regulating both primary sensitization and the subsequent balance between immune progression or regulation that determines either clinical sensitivity or tolerance to mucosal allergens.

How to Apply

We accept the common application available through ERAS online and are a participating program in the National Residency Matching Program. Interviews for selected applicants are held on Thursdays from September through November.

Our fellowship program accepts applicants with U.S. citizenship or ECFMG certified J1 visas without bias towards visa status. There must be a minimum of 3 three years remaining on the applicant’s visa in order to complete fellowship training. Our institutional Graduate Medical Education and ACGME accreditation requirements specify that all applicants must be board eligible/certified in pediatrics as determined by the American Board of Pediatrics.

Our Fellows

First Year Fellows

Awab Ali Ibrahim, MD
Medical School: Weill Cornell Medical College in Qatar
Residency: University of South Alabama
Current Research Interests: TBD
Research Mentor: TBD
SOC Chairperson / Advisor: TBD

Kayla Hartjes, MD
Medical School: University of Massachusetts Medical School
Residency: University of Massachusetts
Current Research Interests: TBD
Research Mentor: TBD
SOC Chairperson / Advisor: TBD

Second Year Fellows

Katherine Olshan, MD
Medical School: Medical College of Wisconsin
Residency: University of Massachusetts
Current Research Interests: Role of breastmilk composition on the development of celiac disease in at risk infants.
Research Mentor: Maureen Leonard, MD, MMSc, and Alessio Fasano, MD
SOC Chairperson / Advisor: TBD

Desiree Sierra Velez, MD
Medical School: University of Puerto Rico Medical School
Residency: Nicklaus Children's Hospital
Current Research Interests: Evidence-based interventions for management of pediatric obesity.
Research Mentor: Lauren Fiechtner, MD, MPH and Elsie Taveras, MD, MPH
SOC Chairperson / Advisor: TBD

Third Year Fellows

Rasha Elmaoued, MD
Medical School: University of New Mexico School of Medicine
Residency: University of New Mexico School of Medicine Pediatric Residency Program
Current Research Interests: Characterizing the role of microRNAs in the pathogenesis of Hepatitis B and lean NAFLD
Research Mentor: Esperance Schaefer, MD, MPH and Raymond Chung, MD
SOC Chairperson / Advisor: Kriston Ganguli, MD (Chair); Uzma Shah, MBBS; Esperance Schaefer, MD, MPH; Raymond Chung, MD

Meryl Perlman, MD
Medical School: University of Chicago Division of the Biological Sciences, the Pritzker School of Medicine
Residency: MassGeneral Hospital for Children
Current Research Interests: The effect of nutrient deprivation on enteric infections in a malnourished organoid model of the duodenum.
Research Mentor: Christina Faherty, PhD, and Alessio Fasano, MD
SOC Chairperson / Advisor: Christopher Moran, MD (Chair); Jason Harris, MD; Harland Winter, MD; Christina Faherty, PhD; Alessio Fasano, MD


MGHfC Gastroenterology Nutrition Fellowship

  •  Near Public Transit
  •  Accessible
  • Phone: 617-724-2561
  • Fax: 617-724-2710

Program Coordinator:

Cate Kron
Phone: 617-726-1450
Fax: 617-724-2710


Program Director:

Gary J. Russell, MD
Phone: 617-726-1450
Fax: 617-724-2710