Journal of Molecular Diagnostics : JMD

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder primarily caused by the deletion or mutation of the survival motor neuron 1 (SMN1) gene. This study assesses the diagnostic potential of long-read sequencing (LRS) in three patients with SMA. For Patient 1, who has a heterozygous SMN1 deletion, LRS unveiled a missense mutation in SMN1 exon 5. In Patient 2, an Alu/Alu-mediated rearrangement covering the SMN1 promoter and exon 1 was identified through a blend of multiplex ligation-dependent probe amplification, LRS, and Gap-PCR...

Small blue round cell sarcomas (SBRCSs) are a heterogeneous group of tumors with overlapping morphologic features but markedly varying prognosis. They are characterized by distinct chromosomal alterations, particularly rearrangements leading to gene fusions, whose detection currently represents the most reliable diagnostic marker. Ewing sarcomas (ESs) are the most common SBRCSs, defined by gene fusions involving EWSR1 and transcription factors of the ETS gene family, while the most frequent non-EWSR1-rearranged SBRCSs harbor a CIC rearrangement...

Soft tissue and bone tumours represent a heterogeneous group of tumours encompassing more than 100 histological subtypes today. Identifying genetic aberrations is increasingly important in these tumours for accurate diagnosis. While gene mutations are typically detected by second generation sequencing, the identification of structural variants (SVs) and copy number alterations (CNAs) remains challenging and requires various cytogenetic techniques including karyotyping, fluorescent in situ hybridisation and arrays, each having important limitations...

Microarray-based methylation profiling has emerged as a valuable tool for refining diagnoses and revealing novel tumor subtypes, particularly in central nervous system tumors. Despite the increasing adoption of this technique in clinical genomic laboratories, no technical standards have been published in establishing minimum criteria for test validation. A working group with experience and expertise in DNA-based methylation profiling tests on CNS tumors collaborated to develop practical discussion points and focus on important considerations for validating this test in clinical laboratory settings...

Fast and accurate diagnosis of bloodstream infection is necessary to inform treatment decisions for septic patients, who face hourly increases in mortality risk. Blood culture remains the gold standard test but typically requires ∼15 hours to detect the presence of a pathogen. Here, the potential for universal digital high-resolution melt (U-dHRM) analysis to accomplish faster broad-based bacterial detection, load quantification, and species-level identification directly from whole blood is assessed...

Myeloid neoplasms are clonal disorders that arise via acquisition of genetic mutations leading to excessive proliferation and defective differentiation. Mutational profiling is vital as it has implications on diagnosis, prognosis, and therapeutic decision making. Next generation sequencing (NGS) has become a mainstay in the evaluation of myeloid malignancies, as it enables efficient characterisation of multiple genetic changes. Herein the analytical validation of the 37-gene Archer VariantPlex Core Myeloid panel is reported, using 58 DNA specimens with 87 single nucleotide variants (SNV) and 23 insertions/deletions (INDEL)...

Inherited iron metabolism defects are possibly missed or underdiagnosed in iron-deficient endemic settings due to a lack of awareness or a methodical screening approach. Hence, we planned a systematic evaluation of anemia cases (2019-2021) based on clinical phenotype, normal screening tests (HPLC, alpha gene sequencing, ESR, CRP, tTG), and abnormal iron profile by targeted NGS (26 gene-panel) supplemented with whole exome, MLPA/mtDNA sequencing and CMA. Novel variants in ALAS2, STEAP3, and HSPA9 genes were functionally validated...

Trypanosomatids, including Trypanosoma and Leishmania species, present significant medical and veterinary challenges causing substantial economic losses, health complications, and even fatalities. Diagnosing and genotyping these species and their genotypes is often complex, involving multiple steps. This study aimed to develop an amplicon-based sequencing (ABS) method utilizing Oxford Nanopore long-read sequencing to enhance Trypanosomatid detection and genotyping. The 18S rDNA gene was targeted for its inter-species conservation...

Several in silico annotation-based methods have been developed to prioritize variants in exome sequencing analysis. This study introduces a novel metric, the Significance Associated with Phenotypes (SAP) score, which generates a statistical score by comparing an individual's observed phenotypes against existing gene-phenotype associations. To evaluate the SAP score, a retrospective analysis was performed on 219 exomes. Among them, 82 family-based and 35 singleton exomes had at least one disease-causing variant explaining the patient's clinical features...

Chimerism testing supports the study of engraftment and measurable residual disease (MRD) in patients after allogeneic hematopoietic stem cell transplant. In chimerism MRD, relapse can be predicted by increasing mixed chimerism (IMC), recipient increase ≥0.1% in peripheral blood, and proliferating recipient cells as a surrogate of tumor activity. Conventionally, the combination of short-tandem repeat (STR) and quantitative PCR (qPCR) was needed to ensure assay sensitivity and accuracy in all chimerism status...

Human papillomavirus (HPV)-associated cancers, including oropharyngeal squamous cell carcinoma (HPV + OPSCC), cervical cancer, and squamous cell carcinoma of the anus (HPV + SCCA), release circulating tumor HPV DNA (ctHPVDNA) into the blood. The diagnostic performance of ctHPVDNA detection depends on the approaches used and the individual assay metrics. A comparison of these approaches has not been systematically performed to inform expected performance, which in turn affects clinical interpretation...

As the number of genes associated with various germline disorders continues to grow, it is becoming more difficult for clinical laboratories to maintain separate assays for interrogating disease-focused gene panels. One solution to this challenge is termed slice testing, where capture backbone is used to analyze data specific to a set of genes, and for this article, we will focus on exome. A key advantage to this strategy is greater flexibility by adding genes as they become associated with disease or the ability to accommodate specific provider requests...

Cell-free DNA (cfDNA) serves as a valuable biomarker for early disease detection and monitoring. However, the use of cfDNA for analysis faces challenges owing to general low but variable abundance and fragmentation. Preanalytical factors, including cfDNA extraction, impact cfDNA quality and quantity. Efficient and robust cfDNA extraction is essential for reliable results in downstream applications, and various commercial extraction methods exist, each with trade-offs. To aid researchers and clinicians in choosing the proper cfDNA extraction method, manual, semiautomated, and automated methods were evaluated, including the QIAamp Circulating Nucleic Acid Kit (manual and QIAcube), QIAamp MinElute ccfDNA Kit (QIAcube), and QIAsymphony DSP Circulating DNA Kit (QIAsymphony)...

This study reports the development of an exome capture-based RNA-sequencing assay to detect recurring and novel fusions in hematologic, solid, and central nervous system tumors. The assay used Twist Comprehensive Exome capture with either fresh or formalin-fixed samples and a bioinformatic platform that provides fusion detection, prioritization, and downstream curation. A minimum of 50 million uniquely mapped reads, a consensus read alignment/fusion calling approach using four callers (Arriba, FusionCatcher, STAR-Fusion, and Dragen), and custom software were used to integrate, annotate, and rank the candidate fusion calls...

An ever-growing catalog of human variants is hosted in the ClinVar database. In this database, submissions on a variant are combined into a multisubmitter record; and in the case of discordance in variant classification between submitters, the record is labeled as conflicting. The current study used ClinVar data to identify characteristics that would make variants more likely to be associated with the conflict class of variants. Furthermore, the Extreme Gradient Boosting algorithm was used to train classifier models to provide prediction of classification discordance for single submission variants in ClinVar database...

Detection of cancer-associated gene fusions is crucial for diagnosis, prognosis, and treatment selection. Many bioinformatics tools are available for the detection of fusion transcripts by RNA sequencing, but there are fewer well-validated software tools for DNA next-generation sequencing (NGS). A 542-gene solid tumor NGS panel was designed, with exonic probes supplemented with intronic bait probes against genes commonly involved in oncogenic fusions, with a focus on lung cancer. Three software tools for the detecting gene fusions in this DNA-NGS panel were selected and evaluated...

The aim of this study is to evaluate the clinical validity of monitoring urine pellet DNA (upDNA) of bladder cancer (BC) by digital PCR (dPCR) as a biomarker for early recurrence prediction, treatment efficacy evaluation, and no-recurrence corroboration. Tumor panel sequencing was first performed to select patient-unique somatic mutations to monitor both upDNA and ctDNA by dPCR. For longitudinal monitoring using upDNA as well as plasma circulating tumor DNA (ctDNA), an average of 7.2 (range, 2-12) time points per case were performed with the dPCR assay for 32 previously treated and untreated patients with BC...

The utility of the next-generation sequencing (NGS) panel could be increased in hereditary peripheral neuropathies, given that the duplication of PMP22 is a major abnormality. In the present study, the analytical performance of an algorithm for detecting PMP22 copy number variation (CNV) from the NGS panel data was evaluated. The NGS panel covers 141 genes, including PMP22 and five genes within 1.5-Mb duplicated region at 17p11.2. CNV calling was performed using a laboratory-developed algorithm. Among the 92 cases subjected to targeted NGS panel from March 2018 to January 2021, 26 cases were suspicious of PMP22 CNV...

There are limited data on the prevalence of next-generation sequencing (NGS) in the United States (US), especially in light of the increasing importance of identifying actionable oncogenic variants due to molecular biomarker-based therapy approvals. This retrospective study of adult patients with select metastatic solid tumors and central nervous system tumors from the Optum Clinformatics Data Mart US healthcare claims database (January 1, 2014-June 30, 2021; N=63,209) examined NGS utilization trends over time...

Low-grade serous carcinomas (LGSC) probably develop from serous borderline tumors (SBT), where the micropapillary type (mSBT) has the highest risk of progression. The sensitivity of LGSC to standard chemotherapy is limited, so alternative therapeutic approaches are needed, including targeted treatment. However, current knowledge about molecular landscape of LGSC and mSBT is limited. A sample set of 137 pathologically well-defined cases of 40 mSBT and 97 LGSC was analysed using capture DNA NGS (727 genes) and RNA-Seq (147 genes) to show the landscape of somatic mutations, gene fusions, and the expression pattern, as well as their prognostic and predictive relevance...