UCSF Genomics Diagnostics Team Uses Next-Gen Sequencing as a ‘Laboratory-Developed Test’ to Reveal an Elusive Pathogen’s DNA and Save a Teen’s Life
It took UCSF physicians just 48 hours to identify the bacteria in cerebrospinal fluid that was causing fourteen-year-old Joshua Osborn’s hydrocephalus and status epilepticus
There’s rich irony in the FDA’s recent announcement that it would move forward with plans to regulate “laboratory-developed tests ” (LDTs) just weeks after the national media published stories about how innovative use of an LDT helped physicians make an accurate diagnosis that saved the life of seriously-ill 14-year old boy.
Pathologists and clinical laboratory managers may be aware of the case of Joshua Osborn. It was a laboratory-developed test that used next-generation gene sequencing in a unique approach that gave his care team the diagnostic information they needed to select the right therapies for his condition.
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Sequencing Developers’ Unprecedented Success Drives More Ambitious Goals For Genomics X Prize
New Genomic X PRIZE goals/subjects accelerate the drive toward personalized medicine
Swift improvements to the accuracy, speed, and lower cost of rapid gene sequencing have caused the sponsors of the globally-known X PRIZE to revamp their offer of a $10 million award to a team that is first to achieve a defined milestone in whole human genome sequencing.
Pathologists and clinical laboratory managers will be interested to learn how, last month, the X PRIZE Foundation announced a number of major changes to the formerly-named Archon Genomics X PRIZE. Most significantly, competition sponsors changed the subject from 100 genomes from unspecified donors, to genomes from 100 healthy centenarians.
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UCSF Researchers Use Gene Sequencing Test to Diagnose ‘Medical Mysteries’
Single genetic test can identify multiple pathogens and can be used by the UCSF clinical laboratory team to help physicians identify difficult to diagnose diseases
Continuing improvements in gene sequencing technologies and analytical software tools are enabling clinical laboratorians to diagnosis patients who have challenging symptoms. One such example is a new genomic test developed by researchers at University California, San Francisco (UCSF). The single test analyzes both RNA and DNA to detect almost any type of pathogen that may be the cause of specific illnesses.
The test uses a genomic sequencing technique known as metagenomics next-generation sequencing (mNGS). It works by sequencing genetic material found in blood, tissue, or body fluid samples and compares the sequenced data against a broad database of known pathogens to seek a match. Instead of looking for just one pathogen at a time, mNGS analyzes all of the nucleic acids, RNA, and DNA present in a sample simultaneously to detect nearly all pathogens, including viruses, bacteria, fungi, and parasites.
The mNGS test is not intended to replace existing clinical laboratory tests, but to help physicians diagnose an illness in cases where patients are experiencing severe symptoms, and where initial, commonplace tests are ineffective. In such cases, medical professionals require additional information to achieve a proper diagnosis.
A pair of studies released late last year outlined the specifics and success of the technology. They are “Seven-year Performance of a Clinical Metagenomic Next-generation Sequencing Test for Diagnosis of Central Nervous System Infections,” published in Nature Medicine, and “Laboratory Validation of a Clinical Metagenomic Next-generation Sequencing Assay for Respiratory Virus Detection and Discovery,” published in Nature Communications. Both articles were released on November 12, 2024.
“Our technology is deceptively simple,” said Charles Chiu, MD, PhD (above), professor of laboratory medicine and infectious diseases at UCSF and senior author of the studies in a news release. “By replacing multiple tests with a single test, we can take the lengthy guesswork out of diagnosing and treating infections.” The new technology may help physicians diagnose patients who have challenging symptoms and where current clinical laboratory testing is ineffective at identifying specific pathogens. (Photo copyright: University California San Francisco.)
Diagnostic Armamentarium for Physicians
According to an article published by the American Society for Microbiology (ASM) titled, “Metagenomic Next Generation Sequencing: How Does It Work and Is It Coming to Your Clinical Microbiology Lab?” mNGS is “running all nucleic acids in a sample, which may contain mixed populations of microorganisms, and assigning these to their reference genomes to understand which microbes are present and in what proportions. The ability to sequence and identify nucleic acids from multiple different taxa [plural for taxon] for metagenomic analysis makes this a powerful new platform that can simultaneously identify genetic material from entirely different kingdoms of organisms.”
The researchers developed the mNGS test years ago and it has produced promising results, including:
- Diagnosing cases of encephalitis in transplant recipients to yellow fever in their organ donors.
- Helping to identify the cause of a meningitis outbreak in Mexico among surgical patients.
- Detecting a case of leptospirosis in a patient who was in a medically induced coma, which prompted doctors to prescribe penicillin and resulted in the full recovery of the patient.
- Identifying the cause of neurological infections such as meningitis and encephalitis. The test successfully diagnosed 86% of neurological infections in more than 4,800 spinal fluid samples.
“Our mNGS test performs better than any other category of test for neurologic infections,” said Charles Chiu, MD, PhD, professor of laboratory medicine and infectious diseases at UCSF and senior author of the two studies, in a UCSF news release. “The results support its use as a critical part of the diagnostic armamentarium for physicians who are working up patients with infectious diseases.”
FDA Breakthrough Device Designation
The UCSF test has not yet been approved by the federal Food and Drug Administration (FDA), but it was granted a “breakthrough device” designation by the agency. This classification authorizes labs to use the test as a valid diagnosis method due to its potential ability to benefit patients.
Chiu told NBC News that the test costs about $3,000 per sample and fewer than 10 labs routinely use it due to several issues.
“Traditionally, it’s been used as a test of last resort, but that’s primarily because of issues involving, for instance, the cost of the test, the fact that it’s only available in specialized reference laboratories, and it also is quite laborious to run,” he said.
This type of lab testing is not feasible for most hospitals as it is costly and complicated, and because physicians may need assistance from clinical laboratory personnel who have the appropriate expertise to properly read test results.
“This just is not something that a clinical lab will be doing until somebody commercially puts it in a box with an easy button,” Susan Butler-Wu, PhD, associate professor of clinical pathology at the University of Southern California (USC), told NBC News. “It’s not a one-stop shop. It just can be helpful as an additional tool.”
Although the technology has some limitations, Chiu says the research performed by his team “raises the possibility that we perhaps should be considering running this test earlier” in symptomatic patients. He hopes the test will be used on a widespread basis in hospitals to diagnose various illnesses in the future.
“We need to get the cost down and we need to get the turnaround times down as well,” he told NBC.
Definitive Tool for Pathogen Detection
To increase access to the technology, Chiu and his colleagues founded Delve Bio, which is now the exclusive provider of the mNGS tool created at UCSF. In December, the company announced the commercial launch of Delve Detect, a metagenomic test for infectious diseases. According to its website, Delve Detect “offers genomic testing of cerebrospinal fluid (CSF) for more than 68,000 pathogens, with 48-hour turnaround time and metagenomics experts readily available to discuss results.”
“These findings support including mNGS as a core tool in the clinical workup for CNS [central nervous system] infections,” said Steve Miller, MD, PhD, UCSF volunteer clinical professor, laboratory medicine, and chief medical officer of Delve Bio in the UCSF news release. “mNGS offers the single most unbiased, complete and definitive tool for pathogen detection. Thanks to its ability to quickly diagnose an infection, mNGS helps guide management decisions and treatment for patients with meningitis and encephalitis, potentially reducing healthcare costs down the line.”
This mNGS test may prove to have the potential to greatly improve medical care for some infections and possibly expedite the detection of new viral threats. It is probable that clinical laboratories will soon be learning about and performing more tests of this nature in the future.
—JP Schlingman
Related Information:
Cutting-edge Test Uses DNA Sequencing to Yield Diagnoses for Some Medical Mysteries
One Genomic Test Can Diagnose Nearly Any Infection
Rapid Test Can ID Unknown Causes of Infections Throughout the Body
Delve Bio Announces Launch of its Groundbreaking Genomic Infectious Disease Test, Delve Detect
Next-Generation Sequencing Allows Mayo Clinic Researchers to Produce Large Dataset of Patients’ Exomes
Nearly 100,000 patients submitted saliva samples to a genetic testing laboratory, providing insights into their disease risk
Researchers at Mayo Clinic have employed next-generation sequencing technology to produce a massive collection of exome data from more than 100,000 patients, offering a detailed look at genetic variants that predispose people to certain diseases. The study, known as Tapestry, was administered by doctors and scientists from the clinic’s Center for Individualized Medicine and produced the “largest-ever collection of exome data, which include genes that code for proteins—key to understanding health and disease,” according to a Mayo Clinic news release.
For our clinical laboratory professionals, this shows the keen interest that a substantial portion of the population has in using their personal genetic data to help physicians identify their risk for many diseases and types of cancer. This support by healthcare consumers is a sign that labs should be devoting attention and resources to providing these types of gene sequencing services.
As Mayo explained in the news release, the exome includes nearly 20,000 genes that code for proteins. The researchers used the dataset to analyze genes associated with higher risk of heart disease and stroke along with several types of cancer. They noted that the data, which is now available to other researchers, will likely provide insights into other diseases as well, the news release notes.
The Mayo Clinic scientists published their findings in Mayo Clinic Proceedings titled, “Mayo Clinic Tapestry Study: A Large-Scale Decentralized Whole Exome Sequencing Study for Clinical Practice, Research Discovery, and Genomic Education.”
“What we’ve accomplished with the Tapestry study is a blueprint for future endeavors in medical science,” said gastroenterologist and lead researcher Konstantinos Lazaridis, MD (above), in the news story. “It demonstrates that through innovation, determination and collaboration, we can deeply advance our understanding of DNA function and eventually other bio-molecules like RNA, proteins and metabolites, turning them into novel diagnostic tools to improve health, prevent illness, and even treat disease.” Some of these newly identified genetic markers may be incorporated into new clinical laboratory assays. (Photo copyright: Mayo Clinic.)
How Mayo Conducted the Tapestry Study
One notable aspect of the study was its methodology. The study launched in July 2020 during the COVID-19 pandemic. Since many patients were quarantined, researchers conducted the study remotely, without the need for the patients to visit a Mayo facility. It ran for five years through May 31, 2024. The news release notes that it’s the largest decentralized clinical trial ever conducted by the Mayo Clinic.
The researchers identified 1.3 million patients from the main Mayo Clinic campuses in Minnesota, Arizona, and Florida who met the following eligibility criteria:
- Participants had to be 18 or older,
- they had to have internet and email access, and
- be sufficiently proficient in speaking and reading English.
Patients with certain medical conditions, such as dementia and hematologic cancers, were excluded.
More than 114,000 patients consented to participate, but some later withdrew, resulting in a final sample of 98,222 individuals. Approximately two-thirds were women. Mean age was 57 (61.9 for men and 54.3 for women).
“It was a tremendous effort,” said Mayo Clinic gastroenterologist and lead researcher Konstantinos Lazaridis, MD, in the news release. “The engagement of such a number of participants in a relatively short time and during a pandemic showcased the trust and the dedication not only of our team but also of our patients.”
He added that the researchers “learned valuable lessons about some patients’ decisions not to participate in Tapestry, which will be the focus of future publications.”
Three Specific Genes
Enrolled patients were invited to visit a website, where they could view a video and submit an eligibility form. Once approved, they completed a digital consent agreement and received a saliva collection kit. Participants were also invited to provide information about their family history.
Helix, a clinical laboratory company headquartered in San Mateo, Calif., performed the exome sequencing.
Though Helix performed whole exome sequencing, the researchers were most interested in three specific sets of genes:
- BRCA1 and BRCA2, associated with increased risk of breast and ovarian cancer in women, and breast and prostate cancer in men.
- MLH1, MSH2, MSH6, PMS2, and EPCAM [epithelial cell adhesion molecule], which is associated with Lynch syndrome and linked to higher risk of colorectal and uterine cancers.
- APOB, LDLR, PCSK9, and LDLRAP1, associated with familial hypercholesterolemia, which is linked to early-onset cardiovascular disease.
Patients received clinical results directly from Helix along with information about their ancestry. Clinical results were also transmitted to Mayo Clinic for inclusion in patients’ electronic health records (EHRs).
Among the participants, approximately 1,800 (1.9%) had what the researchers described as “actionable pathogenic or likely pathogenic variants.” About half of these were BRCA1/2.
These patients were invited to speak with a genetic counselor and encouraged to undergo additional testing to confirm the variants.
Tapestry Genomic Registry
In addition to the impact on the participants, Mayo Clinic’s now has an enormous amount of raw sequencing data stored in the Tapestry Genomic Registry, where it will be available for future research.
The database “has become a valuable resource for Mayo’s scientific community, with 118 research requests submitted,” the researchers wrote in the news release. Mayo has distribution more than a million exome datasets to other genetic researchers.
“What we’ve accomplished with the Tapestry study is a blueprint for future endeavors in medical science,” Lazaridis noted. “It demonstrates that through innovation, determination, and collaboration, we can deeply advance our understanding of DNA function and eventually other bio-molecules like RNA, proteins and metabolites, turning them into novel diagnostic tools to improve health, prevent illness, and even treat disease.”
Everything about this project is consistent with precision medicine, and the number of individuals discovered to have risk of cancers is relevant. Clinical laboratory professionals understand these ratios and the importance of early detection and early intervention.
—Stephen Beale
Related Information:
Mayo Clinic’s Largest-Ever Exome Study Offers Blueprint for Biomedical Breakthroughs
