Our Team

Michael J. Rosen, MD, MSCI

Stanford University Endowed Professor for Pediatric IBD and Celiac Disease; Director, Stanford Medicine Children’s Health Center for IBD and Celiac Disease

Dr. Michael J. Rosen is a pediatric gastroenterologist and physician scientist, who has been devoted to inflammatory bowel disease (IBD) research since beginning medical training over 20 years ago. He serves as the Director of the Stanford Medicine Children’s Health Center for IBD and Celiac Disease. Dr. Rosen has expertise crossing mucosal immunology and epithelial biology, formal training and experience in clinical and translational investigation with human biospecimens, and direct insight regarding the important clinical challenges caring for children with complicated IBD. His translational research program focuses on how the immune system regulates epithelial function in chronic intestinal inflammation as it relates to IBD. Dr. Rosen’s clinical research program has focused on optimization of anti-TNF therapy in pediatric IBD. His research laboratory has demonstrated a protective role for IL33, a cytokine that induces type 2 cytokines from T cells an innate lymphoid cells (ILCs), in acute oxazolone colitis through preservation of epithelial goblet cells and barrier function. In line with this finding, his research has also shown in a large prospective patient cohort that mucosal expression of type 2 and type 17 immune response genes distinguishes ulcerative colitis (UC) from colon-only Crohn’s disease, and that type 2 gene expression is associated with superior clinical outcome in pediatric UC. The Rosen laboratory has now developed an organoid-immune cell in vitro culture system to demonstrate the ILC2-dependent mechanism through which IL33 induces goblet cell differentiation in the intestinal epithelium. Dr. Rosen led the multicenter study Anti-TNF for Refractory Colitis in Hospitalized Children (ARCH) Study, and he currently Co-Chairs the Crohn's & Colitis Foundations Cohort for Pediatric Translational and Clinical Research in IBD (CAPTURE IBD) and PRO-KIIDS Pediatric IBD clinical research network.

Dorsey Bass, MD

Associate Professor, Pediatric Gastroenterology, Hepatology, and Nutrition

Dr. Dorsey Bass received his medical degree from Vanderbilt University in Nashville, then proceeded on to complete residency and fellowship training in the city of Boston at Boston City Hospital and Massachusetts General Hospital, respectively. His professional expertise is in the management and treatment of gastrointestinal diseases in children, particularly inflammatory bowel disease. His research background includes more than 15 years in basic and clinical virology of diarrheal agents and more recently a strong interest in cost effective quality care for patients with inflammatory bowel disease. His research experience and more than 25 years of practical clinical work inform his work to find a more appropriate therapy for acute and chronic C. difficile colitis.

Rachel Bensen, MD, MPH

Clinical Associate Professor, Pediatric Gastroenterology, Hepatology, and Nutrition

Dr. Rachel Bensen is a Clinical Associate Professor with Pediatric Gastroenterology, Hepatology and Nutrition at Stanford University School of Medicine. Her clinical work currently focuses on care of children, teens and young adults with inflammatory bowel disease, chronic liver disease and transplant – including chronic GI diseases, requiring long term therapy, usually with immunosuppressive medications. She is currently a co-investigator on a project entitled “Bay Area Implementation of NICH (Novel Interventions in Children’s Healthcare)” that is funded by the Helmsley Charitable Trust and aims to provide additional support to children and their families with complex and chronic conditions. The proposed project fits well with her interests in improvement science and clinical hepatology experience. The proposed project is an innovative approach to promote early diagnosis and early intervention in a structured, well studied fashion which has the potential to have a meaningful impact on children born with biliary atresia.

Ruben Colman, MD, PhD

Assistant Professor, Pediatric Gastroenterology, Hepatology, and Nutrition

Dr. Ruben Colman is an Assistant Professor of Pediatrics in the Division of Gastroenterology, Hepatology and Nutrition at the Stanford Medicine Children’s Health Center for IBD and Celiac Disease. As a physician-scientist he specializes in the care of children with chronic inflammatory bowel diseases (IBD) and further studies how to improve care and disease outcomes for these patients. Dr. Colman’s research seeks to understand person-specific factors that impact the efficacy of novel therapeutics, and identify new ways to use this information to positively impact the effect and durability of medication. He concurrently completed a PhD specializing in pharmacokinetics and pharmacodynamics titled: “Precision Dosing and Personalized Medicine in Pediatric Inflammatory Bowel Disease” which he will defend at the University of Amsterdam in June 2023. Clinically, with his passion to innovate care for children with IBD through personalized medicine, Dr. Colman is pioneering the implementation of point-of-care intestinal ultrasound during routine clinic visits at Stanford/Lucile Packard Children’s Hospital. The opportunity to utilize these ultrasound exams will further advance state of the art care and accelerate the ability to make treatment decisions in an efficient, minimally invasive, and patient-oriented manner.

Alka Goyal, MD

Clinical Professor; Interim Associate Chief of Clinical Affairs; Pediatric Gastroenterology, Hepatology, and Nutrition

Dr. Alka Goyal is a Clinical Professor of Pediatrics at Stanford University School of Medicine, and the Interim Associate Chief of Clinical Affairs for the Pediatric Division of Gastroenterology, Hepatology and Nutrition. Dr. Goyal has extensive research experience in both clinical and translational research; she is the co-PI and co-I on several active research studies, such as prospective, retrospective, and observational studies. Dr. Goyal’s training under the mentorship of Dr. Deborah Rubin at Washington University, St. Louis, Missouri laid a strong foundation for her in basic science research. It is here during her research fellowship that she studied the “Role of Epimorphin on Gut Morphogenesis.” Dr. Goyal then worked as a full-time clinical faculty at University of Pittsburgh. Here, she had the opportunity to serve as a site investigator or co-investigator in several multicenter clinical-translational studies. Dr. Goyal gained expertise in clinical translational research in children by active participation in several multicenter studies including Very Early Onset IBD (NEOPICS), RISK (Risk Stratification and Identification of Immunogenetic and Microbial Markers of Rapid Disease Progression in Children with Crohn’s Disease), PROTECT (Predicting Response to Standardized Pediatric Colitis Therapy) and autologous stem cell transplant in medically refractory Crohn’s disease.  Dr. Goyal also conducted a single center study under an IND on the therapeutic potential of gut microbiota transplantation in inflammatory bowel disease. Dr. Goyal was the site PI for the PRODUCE (Personalized Research on Diet in Ulcerative Colitis and Crohn’s Disease) study and NIH funded “Growth Study” until her move to Stanford University in January 2020. Dr. Goyal’s goal is to provide state of the art comprehensive care to our young patients suffering from IBD using the least immunosuppressive regimens.

Jonathan Moses, MD

Clinical Associate Professor, Pediatric Gastroenterology, Hepatology, and Nutrition; Endowed IBD Medical Director, Stanford Medicine Children’s Health Center for IBD and Celiac Disease

Dr. Jonathan Moses is a clinical associate professor of pediatric gastroenterology and the Inaugural Medical Director of the IBD Program at the Lucile Packard Children’s Hospital. He completed his medical education at The Ohio State University College of Medicine in 2005, followed by a residency in Pediatric Gastroenterology at Nationwide Children's Hospital in Ohio in 2008. Dr. Moses further honed his expertise through a fellowship at the prestigious Cleveland Clinic Children's Pediatric Gastroenterology Department in 2012. With his extensive training and experience, Dr. Moses is well-equipped to provide expert care and specialized treatment to young patients with gastrointestinal disorders.

Michael Schumacher, PhD

Assistant Professor, Pediatric Gastroenterology, Hepatology, and Nutrition 

Dr. Michael Schumacher is a gastrointestinal physiologist focused on discovering new therapeutic targets and regenerative medicine approaches for inflammatory bowel disease (IBD), including ulcerative colitis and Crohn’s disease. His research centers on how intestinal tissues interpret, respond to, and recover from inflammation, with particular emphasis on how immune signals shape epithelial function, tissue remodeling, and mucosal healing. Work in his lab spans both epithelial and immune biology, aiming to define mechanisms that can be leveraged for future therapies. His team integrates large-scale transcriptomic analysis with organoid and physiological models to identify fundamental regulators of intestinal health and disease. Findings from the Schumacher lab have advanced our understanding of how key epithelial cell populations remodel during disease and highlight the colonic crypt base as a critical acute-response hub for health during injury and inflammation. Assistant Professor, Pediatric Gastroenterology, Hepatology, and Nutrition

Ann Ming Yeh, MD

Clinical Professor, Pediatric Gastroenterology, Hepatology, and Nutrition

Dr. Ann Ming Yeh is a Clinical Professor of Pediatric Gastroenterology at Stanford University. Her research focuses on diet therapies, nutrition, and integrative medicine in pediatric gastroenterology. She has presented her work on various topics at national meetings and completed a two-year fellowship in integrative medicine. Dr. Yeh takes a comprehensive, evidence-based approach to patient care and is a board-certified medical acupuncturist. She currently serves as the program director for the Pediatric Integrative Medicine fellowship at Stanford.

Matilda Fresk, MS

Biorepository Manager

• Matilda Fresk oversees the administration and execution of the IBD and Celiac Disease Biorepository, including development of standard operating procedures, sample processing, biospecimen shipment and transportation, inventory management and distribution, and coordination with the Clinical and Translational Research Unit, BioBank, and other research cores.

  Matilda possesses several years of experience at the intersection of translational research, biobanking, and clinical diagnostics. She has managed human biospecimens in both hospital and academic settings, with expertise in sample handling, assay development, molecular diagnostics, and maintaining data integrity under clinical timelines. Most recently, she served as a research engineer in the Department of Protein Science at KTH Royal Institute of Technology, where she coordinated a clinical collaboration with the Karolinska Institute on autoimmune disease research, performed ex vivo whole blood assays, and prepared patient-derived biospecimens for RNA sequencing and flow cytometry–based immune profiling.

  Matilda earned both her BSc in Biotechnology and her MSc in Medical Biotechnology from KTH Royal Institute of Technology. Originally from Sweden, she is now based in the Bay Area. Outside of work, she enjoys spending time with her husband and two dogs and growing vegetables.

Andrew Jung

Clinical Research Coordinator Associate

Andrew Jung has joined our Clinical Research Coordinator (CRC) staff starting in May 2026. He graduated from Case Western Reserve University with a Bachelor of Arts in Psychology. Prior to joining the center, he worked as a CRC at the Child Wellness Lab at Stanford, where he studied childhood wellness and resilience through hair biomarkers and developmental outcomes in healthy children. In this role, he will collaborate with pediatric IBD patients and their families to advance understanding of precision care and individualized treatment approaches through research. In his free time, Andrew enjoys automotive events, traveling, and exploring art museums.

Javier Lopez Rivera, PhD

Bioinformatician

Dr. Lopez-Rivera recently completed his PhD in Molecular Medicine from the Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, bringing with him a wealth of knowledge and experience. His background uniquely positions him to collaborate closely with clinicians and researchers in analyzing high-order genomics, transcriptomics, microbial, single-cell, and clinical data. In his role, Dr. Riveria will play a vital part in our research efforts focused on pediatric inflammatory bowel disease (IBD) and celiac disease. His responsibilities include the analysis of complex datasets and the development and implementation of innovative bioinformatics methodologies and tools tailored specifically to the needs of our research in these areas. When not at work, Dr. Rivera finds pleasure in cooking, staying active with workouts and weightlifting, and video games, particularly those of the role-playing genre.

Lianne Saussy

Clinical Research Coordinator Associate

Lianne graduated from Johns Hopkins University in May 2026 with a Bachelor of Science in Molecular and Cellular Biology and a second major in Psychology. Before joining, Lianne was a Clinical Research Intern on a Phase 4 Dupilumab clinical trial at the Icahn School of Medicine. She was also a Research Assistant in the Hussain Shuler Neuroscience Laboratory at JHMI, where she studied the role of the visual cortex in decision-based reward timing. As a CRCA, she will be spending the majority of her time on the MUSIC-CD study in children with Crohn’s disease. In her free time, Lianne enjoys running, hiking, cooking, and exploring the Bay Area.

Peacha Sokzini, MS

Senior Clinical Research Coordinator

Peacha Sokzini joined the clinical research coordinator associate (CRCA) team for the Stanford Medicine Children’s Health Center for IBD and Celiac Disease in December 2023. Her focus as a CRCA is on celiac disease research and medical data collection, and she works on studies that include looking for treatment options or lifestyle modifications that can improve the quality of life for pediatric patients with IBD and celiac disease. Before becoming a CRCA, Peacha worked as a middle school science teacher in San Jose and is excited to continue working with children and families in a medical setting. Peacha graduated in May 2023 from Keck Graduate Institute with a Master of Science in Applied Life Sciences and received her undergraduate degree from Tulane University in New Orleans. Outside of work she enjoys dancing, crocheting, cooking, and traveling.

Tricina Thomas

Clinical Research Coordinator Associate

Tricina Thomas joined the Clinical Research Coordinator Associate team at Stanford Medicine Children's Health Center for IBD and Celiac Disease in 2026. She supports pediatric inflammatory bowel disease and Celiac disease research through study coordination, participant engagement and data management. Tricina earned her Bachelors of Science in Communicative Disorders from San Francisco State University and brings experience in leadership, behavioral therapy and phlebotomy. She is passionate about improving health and quality of life of children and families through clinical research and looks forward to continuing to learn and grow in the field. Outside of work, Tricina. enjoys going to the gym, hiking, discovering new cafes for matcha lattes and spending time with her two black cats.