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$2.9 million NIH grant to study the genetics of IBD in the Hispanic population

$2.9 million NIH grant to study the genetics of IBD in the Hispanic population

Newswise – After studying the genetic sequences of more than 100,000 people, researchers across the country have begun uncovering the root causes of inflammatory bowel disease (IBD), Crohn’s disease and ulcerative colitis. But those studies have a glaring flaw: they are based primarily on genetic data, almost exclusively from individuals of European descent.

Now researchers at the University of Miami Miller School of Medicine are trying to change that. Maria Abreu, physicianthe director of the Miller School’s Crohn’s and Colitis Center, and Jacob McCauley, Ph.D.director of the Center for Genome Technology and Biorepository Facility, have been awarded a $2.9 million grant from the National Institutes of Health (NIH) to collect the genetic data of more than 3,000 Hispanic individuals over the next five years and analyze it, to better understand IBD in that community.

Hispanics have much lower rates of IBD than people in the US or Europe, but Dr. Abreu began to see Latin Americans developing IBD quickly after moving to the US. She wanted to study those changes, but with so few Spanish gene sequences available to study, Dr. Abreu knew she had to expand the pool.

Officials at the NIH felt the same way, writing in the grant announcement that there is an “urgent need” to increase the diversity of genetic sequencing.

“The NIH now recognizes that Hispanic and Black people, who make up a very significant percentage of our country, are underrepresented in all of these studies,” said Dr. Abreu.

‘More statistical power in the figures’

drs. Abreu and McCauley have already collected the DNA of nearly 2,000 Hispanic individuals from South Florida. The NIH grant will allow them to raise an additional 3,000 for the IBD study.

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Dr. McCauley says those large numbers are crucial. Humans share 99 percent of their genes, but, he said, “that one percent is a lot.” If a study has too few genetic sequences, the differences between them may be random or insignificant. More genetic sequences allow scientists to identify clearer patterns and zoom in on specific genes that may contribute to diseases and other conditions.

“There’s more statistical power in the numbers,” he said. “We need to change the recruiting and enrollment process and educate these patient populations that haven’t really been approached in the past about these studies, and try to enroll them to help us with these discoveries.”

That’s a far cry from the days when geneticists purposefully sought gene sequences from people with similar ancestral backgrounds, thinking such an approach would make it easier to identify changes in their genetic sequences that cause disease. Now geneticists are struggling to diversify those gene pools after realizing that a more diverse gene pool actually helps them better understand the biology of disease.

“A whole range of genes have been described to increase the risk of IBD, but all have been described in Europeans. But what if the same genes are also found across different ancestries? Well, that means those genes must be very important,” said Dr. Abreu. “We like to blow up how we study these diseases.”

Cuban immigrants see earlier beginnings in recent years

Dr. Abreu does not want to predict outcomes, but her colleague does Oriana Damas, MDfound that Hispanic people can develop IBD after arriving in the US because of the drastic change in their diet, the ever-increasing number of food additives used in the US, and other environmental factors leading to massive changes in their gut bacteria.

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A study led by dr. Damas at the Crohn’s and Colitis Center found that Cuban immigrants developed IBD an average of seven years after immigration, compared with an average of 30 years to illness several decades ago. The NIH study allows her to extend those findings to immigrants from Mexico, Central America, South America and the Caribbean.

“We think the real change that’s happening is diet and gut bacteria,” she said.

drs. Abreu and McCauley are collaborating with six other universities chosen to participate in the NIH grant as Genetics Research Centers within the Inflammatory Bowel Disease Genetics Consortium (IBDGC) to conduct the study. They expect to begin recruiting volunteers to donate blood and saliva samples in early 2023, hoping to attract enough Hispanic individuals with IBD — and without IBD — to study a full range of genetic sequences.

For dr. McCauley, the NIH study represents another step in his ongoing efforts to diversify the gene pool available to scientists. In addition to the work he and Dr. Abreu have already done locally and within the IBDGC, Dr. McCauley also one of the founders of the Alliance for Spanish Multiple Sclerosis Research consortium, which aims to expand knowledge of another complex disease, multiple sclerosis, in Spanish communities. He also participates in the NIHs All Of Us Research Programwhich is trying to collect a million genetic sequences across the country for researchers to use in large-scale research projects.

McCauley said diversifying the genes available to study is especially important in Miami because the community is made up of so many immigrants and people from Latin America.

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“This is the community we serve in South Florida,” he said. “We are one of the most diverse communities in the country. I think that has a lot of value for the research we do.”



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