October 10, 2025

#362 Optical Genome Mapping: Detecting Structural Variants Missed by Traditional Tests

28 minutes

What if we could detect structural changes in DNA that traditional tests often miss? On this episode of DNA Today, we’re diving into optical genome mapping (OGM), a cutting-edge technology transforming how we detect genetic variants and structural abnormalities. We’ll explore what OGM is, how it compares to existing genetic tests, and what it means for patients and families worldwide.

Our guest is Dr. Nikhil Sahajpal, Assistant Director in the Cytogenetics and Molecular Laboratories at the Greenwood Genetic Center (GGC) in Greenwood, SC. He led the validation of OGM at GGC.

He earned his PhD in Pharmaceutical Sciences in India before completing postdoctoral training at Augusta University in Augusta, Georgia, where he focused on advancing molecular and cytogenetic methodologies for prenatal, pediatric, and oncology applications. During his time there, he also played a key role in establishing FDA/EUA-approved diagnostic testing and research for COVID-19.

Dr. Sahajpal began his Laboratory Genetics & Genomics fellowship at GGC in the summer of 2022. During his fellowship, he trained extensively in the implementation and interpretation of molecular and cytogenetic diagnostic tests and led the development and validation of a novel clinical test, optical genome mapping.

Now as an Assistant Director, Dr. Sahajpal continues his innovative work while advancing GGC’s mission of providing state-of-the-art diagnostic tools along with compassionate care for patients and families affected by genetic disorders.

In this conversation, we explore:

OGM basics – what it is, how it works, and why it matters

Why Greenwood Genetic Center adopted OGM and Dr. Sahajpal’s role in leading the project

How OGM compares to karyotyping, microarray, FISH, and NGS

The resolution advantage of OGM and its impact on clinical care

Early success stories where OGM provided answers missed by other methods

Insights from GGC’s study on neural tube defects (NTDs), including the discovery of candidate genes (RMND5A, HNRNPC, FOXD4, and RBBP4)

How OGM could help reduce the diagnostic odyssey for rare disease patients

The future of OGM – will it replace traditional cytogenetic techniques or work alongside them?

Relevant Resources:

Greenwood Genetic Center’s Optical Genome Mapping – Complete and Targeted

Study Using OGM in Neural Tube Defects Reveals Previously Unreported Variants and Candidate Genes with Potential Links to the Devastating Birth Defect

Sahajpal Completes Laboratory Fellowship at GGC and Joins Faculty

Sahajpal NS, Mondal AK, Singh H, Vashisht A, Ananth S, Saul D, Hastie AR, Hilton B, DuPont BR, Savage NM, Kota V, Chaubey A, Cortes JE, Kolhe R. Clinical Utility of Optical Genome Mapping and 523-Gene Next Generation Sequencing Panel for Comprehensive Evaluation of Myeloid Cancers. Cancers (Basel). 2023 Jun 16;15(12):3214. doi: 10.3390/cancers15123214. PMID: 37370824; PMCID: PMC10296552.

Relevant DNA Today Podcast Episode:

#145 Greenwood Genetic Center on Epigenetics

#279 Reflecting on 50 Years of Greenwood Genetic Center

#355 How Genomics Is Transforming Rare Disease Diagnosis in Turkey (discusses dual diagnoses)

Get ready, genetic nerds—another brand-new episode of DNA Today drops this Friday! You can always count on us to deliver fresh content every Friday.

While you wait, why not dive into our library of over 350 episodes? Binge them all on Apple Podcasts, Spotify, our website, or wherever you love to listen—just search “DNA Today.”

Prefer watching? We’ve got you covered! For the past four years, we’ve been recording episodes with video, including some filmed at the iconic NBC Universal Stamford Studios. Check them out on our YouTube channel!

DNA Today is hosted and produced by Kira Dineen, MS, LCGC, CG(ASCP)CM . Our Video Lead is Amanda Andreoli. Our Social Media Lead Liv Davidson. And our logo Graphic Designer is Ashlyn Enokian, MS, CGC.

See what else we are up to on Instagram, X (Twitter), BluSky, Threads, LinkedIn, Facebook, YouTube and our website, DNAToday.com. Questions/inquiries can be sent to [email protected].

...more

View all episodes

By Kira Dineen

4.7

153153 ratings