Real-World Clinical Utility of Targeted RNA Sequencing in Leukemia Diagnosis and Management.

Gene fusions are key drivers in acute leukemia, impacting diagnosis and treatment decisions. We analyzed 264 leukemia patients using targeted RNA sequencing with conventional karyotyping and reverse transcription polymerase chain reaction (RT-PCR). Leukemic fusions were detected in 127 patients (48.1%). The new guidelines introduced additional diagnostic criteria, expanding the spectrum of gene fusions. We discovered three novel fusions (RUNX1::DOPEY2, RUNX1::MACROD2, and ZCCHC7::LRP1B). We analyzed recurrent breakpoints for the KMT2A and NUP98 rearrangements. Targeted RNA sequencing showed consistent results with RT-PCR in all tested samples. However, when compared to conventional karyotyping, we observed an 83.3% concordance rate, with 29 cases found only in targeted RNA sequencing, 7 cases with discordant results, and 5 cases found only in conventional karyotyping. For the five cases where known leukemic gene rearrangements were suspected only in conventional karyotyping, we conducted additional messenger RNA sequencing in four cases and proved no pathogenic gene rearrangements. Targeted RNA sequencing proved advantageous for the rapid and accurate interpretation of gene rearrangements. The concurrent use of multiple methods was essential for a comprehensive evaluation. Comprehensive molecular analysis enhances our understanding of leukemia's genetic basis, aiding diagnosis and classification. Advanced molecular techniques improve clinical decision-making, offering potential benefits.

Re-evaluation of a Fibrillin-1 Gene Variant of Uncertain Significance Using the ClinGen Guidelines.

Background: Marfan syndrome (MFS) is caused by fibrillin-1 gene (FBN1) variants. Mutational hotspots and/or well-established critical functional domains of FBN1 include cysteine residues, calcium-binding consensus sequences, and amino acids related to interdomain packaging. Previous guidelines for variant interpretation do not reflect the features of genes or related diseases. Using the Clinical Genome Resource (ClinGen) FBN1 variant curation expert panel (VCEP), we re-evaluated FBN1 germline variants reported as variants of uncertain significance (VUSs). Methods: We re-evaluated 26 VUSs in FBN1 reported in 161 patients with MFS. We checked the variants in the Human Genome Mutation Database, ClinVar, and VarSome databases and assessed their allele frequencies using the gnomAD database. Patients' clinical information was reviewed. Results: Four missense variants affecting cysteines (c.460T>C, c.1006T>C, c.5330G>C, and c.8020T>C) were reclassified as likely pathogenic and were assigned PM1_strong or PM1. Two intronic variants were reclassified as benign by granting BA1 (stand-alone). Four missense variants were reclassified as likely benign. BP5 criteria were applied in cases with an alternate molecular basis for disease, one of which (c.7231G>A) was discovered alongside a pathogenic de novo COL3A1 variant (c.1988G>T, p.Gly633Val). Conclusions: Considering the high penetrance of FBN1 variants and clinical variability of MFS, the detection of pathogenic variants is important. The ClinGen FBN1 VCEP encompasses mutational hotspots and/or well-established critical functional domains and adjusts the criteria specifically for MFS; therefore, it is beneficial not only for identifying pathogenic FBN1 variants but also for distinguishing these variants from those that cause other connective tissue disorders with overlapping clinical features.

A single-center experience on long-term clinical performance of a rapid SARS-CoV-2 Antigen Detection Test, STANDARD Q COVID-19 Ag Test.

The COVID-19 pandemic in Korea has dynamically changed with the occurrence of more easily transmissible variants. A rapid and reliable diagnostic tool for detection of SARS-CoV-2 is needed. While RT-PCR is currently the gold standard for detecting SARS-CoV-2, the procedure is time-consuming and requires expert technicians. The rapid antigen detection test (RADT) was approved as a confirmatory test on 14 March 2022 due to rapid dissemination of the Omicron variant. The benefits of the RADT are speed, simplicity, and point-of-care feasibility. The aim of our study was to evaluate the clinical performance of RADT compared to RT-PCR in a single center over 15 months, fully covering the SARS-CoV-2 'Variants of Concern (VOC).' A total of 14,194 cases was simultaneously tested by RT-PCR and RADT from January 2021 to March 2022 in Gangnam Severance Hospital and were retrospectively reviewed. PowerChek SARS-CoV-2, Influenza A&B Multiplex Real-time PCR Kit, and STANDARD Q COVID-19 Ag Test were used. Positive rates, sensitivities, specificities, positive predictive values (PPV), and negative predictive values (NPV) were estimated for five periods (3 months/period). Receiver operator characteristic curve (ROC) analysis was performed, and Spearman's rank test assessed the correlation between RT-PCR Ct values and semi-quantitative RADT results. The overall positive rate of RT-PCR was 4.64%. The overall sensitivity and specificity were 0.577 [95% confidence interval (CI) 0.539-0.614] and 0.991 [95% CI 0.989-0.993], respectively. ROC analysis resulted in an area under the curve of 0.786 (P < 0.0001, Yuden's index = 0.568). The PCR positive rates were estimated as 0.11%, 0.71%, 4.51%, 2.02%, and 13.72%, and PPV was estimated as 0.045, 0.421, 0.951, 0.720, and 0.798 in Periods 1, 2, 3, 4, and 5, respectively. A significant and moderate negative correlation between PCR Ct values and semi-quantitative RADT results was observed (Spearman's ρ = - 0.646, P < 0.0001). The RADT exhibited good performance in specimens with low Ct values (Ct ≤ 25.00) by RT-PCR. The PPV was significantly higher in Periods 3 and 5, which corresponds to rapid dissemination of the Delta and Omicron variants. The high PPV implies that individuals with a positive RADT result are very likely infected with SARS-CoV-2 and would require prompt quarantine rather than additional RT-PCR testing. The sensitivity of 0.577 indicates that RADT should not replace RT-PCR. Nonetheless, given the high PPV and the ability to track infected persons through rapid results, our findings suggest that RADT could play a significant role in control strategies for further SARS-CoV-2 variants.

Identification of the novel HLA-DRB4*01:162N allele using next-generation sequencing.

The HLA-DRB4*01:162N allele differs from HLA-DRB4*01:03:01:01 allele by a single nucleotide in codon 131.

A clinicopathologic study of thirty cases of acquired perforating dermatosis in Korea.

BACKGROUND: Acquired perforating dermatosis (APD) is histopathologically characterized by transepidermal elimination of materials from the upper dermis. APD can be divided into four diseases: Kyrle's disease, perforating folliculitis, elastosis perforans serpiginosa, and reactive perforating collagenosis. APD is usually associated with systemic diseases, especially diabetes mellitus or chronic renal failure. So far, there have only been a few Korean studies of APD, which have a limited number of patients. OBJECTIVE: The aim of this study is to evaluate the clinical and histopathologic characteristics of 30 cases of APD and to examine the association with systemic diseases. METHODS: We retrospectively reviewed the medical records and biopsy specimens of 30 patients who were diagnosed with APD. RESULTS: The mean age was 55.5 years, and the average duration of the lesion was 7.8 months. The lower extremities (73.3%) were the most frequently occurring sites of the lesion. Twenty-five patients (83.3%) had pruritus, and Koebner's phenomenon was present in 11 patients. Patients of 63.3% had at least one systemic disease. Diabetes mellitus (n=17, 56.7%) and chronic renal failure (n=10, 33.3%) were the most commonly associated conditions. Most patients received topical steroids (93.3%) and antihistamines (80.0%). The most common histopathologic type was reactive perforating collagenosis (n=23, 73.3%). CONCLUSION: In this study, most patients had a systemic association to the diseases. Therefore, we suggest that further evaluation is necessary for patients who present with APD. This includes reviewing patient's comprehensive past medical history, clinical exam, and additional diagnostic testing to check for the possibility of associated systemic diseases.