# IBD Gene Mapping by Clinical and Population Subset

> **NIH NIH U01** · RBHS-ROBERT WOOD JOHNSON MEDICAL SCHOOL · 2021 · $451,377

## Abstract

PROJECT SUMMARY Inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC) are
complex genetic disorders of the gastrointestinal tract, and a major health burden to patients and society.
Tremendous progress has been made in dissecting IBD genetic etiology with identification of over 200 IBD loci
by genome wide association studies (GWAS) but mainly limited to persons of European ancestry. The IBD
Genetics Consortium (IBDGC) was established to facilitate multicenter collaborative studies of 6 Genetics
Research Centers (GRCs) organized with a Data Coordinating Center (DCC). Our GRC at Johns Hopkins
(JHGRC) has contributed to all IBDGC studies, meeting recruitment objectives and taking roles in IBDGC
leadership positions. Our particular focus is on African American (AA) IBD genetics. We performed the first
large-scale evaluation of European loci in the AA population, replicating several genes, but also finding unique
African-ancestral variants within these loci, as well as identified multiple admixture significant loci. We also
published the first AA IBD genome-wide association study (GWAS), a collaborative effort that identified two
African-specific gene loci, and replicated multiple additional European loci. We have also explored why some
loci with proven risk variants in Europeans and other populations only cause disease in one ancestral
population but not others. More research in AA IBD is needed to understand the etiology of IBD in this
ancestrally distinct, major American population. In this application we will re-evaluate the AA GWAS by better
imputation, evaluate whole genome sequencing data to test low frequency and rare variants, and perform an
evaluation for chromosome X variants. We will recruit a large number of AA IBD patients through our own and
multiple Satellite Recruitment Centers to power a second AA IBD GWAS, both UC and CD, and meta-analyze
with the first to identify more novel loci, identify more African specific risk variants, and replicate known loci for
this population and replicate our admixture loci. We will also incorporate diverse data sources to incorporate
into our GWAS analyses including RNA-Seq currently being generated on lymophoblastoid cell lines from AA
CD cases and controls, and RNA-Seq that we will generate in colonic biopsies from UC cases and controls.
We will evaluate chromatin differences and expression of genes in cell types relevant to IBD from European,
AA and East Asian ancestries in an effort to better understand locus heterogeneity by ancestry. We will
continue to participate in all IBDGC activities to maximize the Impact of IBD genetics research by this
cooperative funding mechanism.

## Key facts

- **NIH application ID:** 10238075
- **Project number:** 5U01DK062431-20
- **Recipient organization:** RBHS-ROBERT WOOD JOHNSON MEDICAL SCHOOL
- **Principal Investigator:** Steven R Brant
- **Activity code:** U01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $451,377
- **Award type:** 5
- **Project period:** 2002-09-30 → 2022-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10238075

## Citation

> US National Institutes of Health, RePORTER application 10238075, IBD Gene Mapping by Clinical and Population Subset (5U01DK062431-20). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10238075. Licensed CC0.

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