# Utilizing long-read sequencing to resolve inconclusive diagnoses and uncertainty in genetic testing

> **NIH NIH R01** · CHILDREN'S HOSP OF PHILADELPHIA · 2024 · $445,000

## Abstract

Abstract
 We propose to use third generation, long-read sequencing (LRS) to resolve inconclusive diagnoses and
maximize the diagnostic yield in patients with suspected Mendelian disorders. The diagnostic yield of whole
exome and genome sequencing stands at 40-50% including a significant proportion of patients receiving an
inconclusive diagnosis. The limitations of the current short-read technologies can be attributed to the negative
and inconclusive molecular diagnoses that prevent us from maximizing the diagnostic yield. Also, the vast
majority of the patients undergo a long diagnostic odyssey due to the practice of sequential testing paradigm.
In the proposed study, we will perform LRS in a cohort of patients with heterogenous pediatric disorders to
resolve a) inconclusive diagnoses in patients with a single disease associated variant in an autosomal
recessive disorder gene, and two disease associated variants in the same gene with unknown phase, and b)
variants of uncertain significance or variant of unknown parent-of-origin in patients with epigenetic or imprinting
disorder. We will determine the diagnostic utility of LRS and its impact on uncertainty in diagnoses against the
current standard of care exome/ genome sequencing. We will build upon the existing resources of our clinical
lab and our own cutting-edge genomic and bioinformatic capabilities. We anticipate that our studies will
contribute new knowledge about the increased diagnostic yield from resolution of inconclusive diagnoses and
lead to the faster adoption of long-reads in clinical settings.

## Key facts

- **NIH application ID:** 10796379
- **Project number:** 1R01HG013355-01
- **Recipient organization:** CHILDREN'S HOSP OF PHILADELPHIA
- **Principal Investigator:** Ramakrishnan Rajagopalan
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $445,000
- **Award type:** 1
- **Project period:** 2024-04-01 → 2028-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10796379

## Citation

> US National Institutes of Health, RePORTER application 10796379, Utilizing long-read sequencing to resolve inconclusive diagnoses and uncertainty in genetic testing (1R01HG013355-01). Retrieved via AI Analytics 2026-05-28 from https://api.ai-analytics.org/grant/nih/10796379. Licensed CC0.

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