Mega Doctor News
By Laura Coverson / Cedars Sinai
Hispanic patients with inflammatory bowel disease (IBD) can experience very different disease patterns depending on whether they have higher African or Amerindian genetic ancestry, according to a large multicenter study led by Cedars-Sinai.
The findings are published in the journal Gastroenterology.
“Among Hispanic patients, higher African ancestry was associated with more severe Crohn’s disease throughout the digestive tract, while higher Amerindian ancestry was linked to disease affecting primarily the colon,” said Talin Haritunians, PhD, the corresponding author of the study and a research associate professor of Medicine at Cedars-Sinai.
Many Hispanic individuals have mixed genetic ancestry that can include Indigenous American ancestry, plus European and African contributions that are the result of centuries of migration and colonization. Amerindian Hispanics have ancestry from indigenous Maya, Aztec and Inca civilizations—and from Spain.
“Our findings show that genetic ancestry can help explain important differences we see in how inflammatory bowel disease affects patients, even within a single ethnic group,” Haritunians said.
An estimated 3 million people in the U.S. have inflammatory bowel disease, according to the Centers for Disease Control and Prevention. The disorder can produce chronic, painful and often destructive inflammation in the digestive tract. The two most common forms of IBD are Crohn’s disease, which can impact any part of the gastrointestinal system, and ulcerative colitis which affects just the colon and rectum.
Ancestry-Aware Analysis
Investigators analyzed genetic and clinical data from more than 7,300 Hispanic patients from the U.S., including Puerto Rico, who had IBD. They also analyzed the same data from patients without the disease. Using a new method of genomic analysis that takes specific ancestry into account, investigators examined how genetic risk and disease presentation and severity varied across ancestral backgrounds.
Hispanic populations often include individuals with mixed genetic ancestry, reflecting a mosaic of Indigenous American, European, and African genetic contributions, the result of centuries of migration and colonization.
“Our group has had a longstanding commitment to extending studies to include diverse populations. Here, we were able to identify ancestry-specific variations in IBD patterns that may be overlooked in broader genetic studies, which often focus on European populations,” said Dermot McGovern, MD, PhD, a co-author of the study and director of Translational Research in the Inflammatory Bowel and Immunobiology Research Institute.
One group in the genetic study was found to be at higher risk for developing a serious and painful form of inflammatory bowel disease.
“Increased risk of penetrating Crohn’s disease was associated with higher African ancestry among Hispanic patients. It is a severe form of IBD in which inflammation extends through the layers of intestinal wall and increases the risk of complications that often require surgery,” McGovern said.
The findings also highlight the importance of examining genetic risk alongside other factors, such as diet and environment, to better understand inflammatory bowel disease across diverse populations.
“Largescale genetic studies that include diverse patients and populations historically underrepresented in research are essential for advancing our understanding of IBD and helping patients,” Haritunians said. “Expanding research in this way will help us move toward more inclusive approaches with the potential to improve treatment options and the lives of patients.”
Additional Cedars-Sinai authors include Dalin Li, PhD; Shaohong Yang, MD; Sweta Sinha, MPH; Emebet Mengesha; Maria A. Quintero, MD; Stephan R. Targan, MD; Shervin Rabizadeh, MD; and Maria T. Abreu, MD.
Other authors include Ashley H. Beecham, PhD; Steven W. Brugger, PhD; Mary F. Davis, PhD; Esther A. Torres, MD; Lissette Gomez, MSc; Paola Lopez-Marte, MD; Mark Daly, PhD; Christine R. Stevens; James S. Leavitt, MD; Oriana M. Damas, MD; Ksenija Sabic; Judy H. Cho, MD; and Jacob L. McCauley, PhD.
Funding: This work was supported by the F. Widjaja Foundation Inflammatory Bowel Disease Institute; the National Institutes of Health/National Institute of Diabetes and Digestive and Kidney Diseases (NIH/NIDDK) through grants U01 DK062413, U24 DK062429-18, U01 DK062422-18, U01 DK062431, and DK062432; the Leona M. and Harry B. Helmsley Charitable Trust; the Fred L. Hartley Family Foundation; the Micky & Madeline Arison Family Foundation Crohn’s & Colitis Discovery Laboratory; the Sanford J. Grossman Charitable Trust; and the National Institutes of Health through grants U54HG003067 and 5UM1HG008895.
Information source: Cedars Sinai Newsroom
