# Multi-organism platform for functional analysis of Undiagnosed Diseases Network (UDN) variants

> **NIH NIH U54** · WASHINGTON UNIVERSITY · 2022 · $300,000

## Abstract

Project Summary
This application proposes the Washington University in St. Louis School of Medicine (WUSM) Model Organism
Screening Core (wuMOSC) as a key asset for Phase II of the NIH Undiagnosed Diseases Network (UDN). The
wuMOSC will evaluate the pathogenicity of genetic variants identified by UDN Clinical Sites in otherwise
undiagnosed participants by leveraging the two well-established animal model organisms Resource Cores: C.
elegans and zebrafish. This approach capitalizes on the experimental advantages of these two model systems,
while avoiding the limitations of individual models. C. elegans allows for extremely rapid and cost-effective variant
evaluation, while zebrafish enables assessment of genes and variants that are not conserved in C. elegans. An
experienced Leadership Team has been assembled that harnesses the collaborative research environment at
WUSM, including the expertise of the superb WUSM clinical partners that constitute the proposed UDN Phase
II WUSM Clinical Site application. Using proven, cutting-edge, and novel bioinformatic approaches, combined
with thoughtful consideration of the advantages and limitations of each model organism, a careful assessment
plan has been defined for determining the putative pathogenicity of nominated variants and prioritizing them for
experimental evaluation by the Resource Cores. The Resource Cores are using efficient and advanced genetic
targeting techniques, including CRISPR/Cas9 to knock-in the human variant into an orthologous gene, knock-
down and loss-of-function assays where appropriate, and overexpression to assess rescue of loss-of-function
or for gain-of-function. Phenotypic analysis of the genetic models will be guided by information in model organism
databases and the literature, as well as patient symptoms. This information will then be applied to the organism-
specific phenotyping pipelines. The UDN Clinical Sites, Steering Committee, and Coordinating Committee will
receive frequent communications regarding plans and results of the wuMOSC, through the activity of the
Administrative Core, which will also disseminate acquired model organism expertise to the wider NIH and other
research communities. As demonstrated over the past four years, the wuMOSC will continue to advance the
diagnostic efforts of the UDN by bioinformatically and experimentally evaluating the potential of disease-causing
variants in the context of disease-specific phenotypes.

## Key facts

- **NIH application ID:** 10600552
- **Project number:** 3U54NS108251-04S1
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** TIM SCHEDL
- **Activity code:** U54 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $300,000
- **Award type:** 3
- **Project period:** 2022-04-02 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10600552

## Citation

> US National Institutes of Health, RePORTER application 10600552, Multi-organism platform for functional analysis of Undiagnosed Diseases Network (UDN) variants (3U54NS108251-04S1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10600552. Licensed CC0.

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