Direct Cortical Stimulation to Probe the Ictogenicity of the Epileptogenic Nodes in Temporal Lobe Epilepsy

Accurate mapping of the seizure onset zone (SOZ) is critical to the success of epilepsy surgery outcomes. Epileptogenicity index (EI) is a statistical method that delineates hyperexcitable brain regions involved in the generation and early propagation of seizures. However, EI can overestimate the SOZ for particular electrographic seizure onset patterns. Therefore, using direct cortical stimulation (DCS) as a probing tool to identify seizure generators, we systematically evaluated the causality of the high EI nodes (>0.3) in replicating the patient's habitual seizures. Specifically, we assessed the diagnostic yield of high EI nodes, i.e., the proportion of high EI nodes that evoked habitual seizures. A retrospective single-center study that included post-stereo encephalography (SEEG) confirmed TLE patients (n = 37) that had all high EI nodes stimulated, intending to induce a seizure. We evaluated the nodal responses (true and false responder rate) to stimulation and correlated with electrographic seizure onset patterns (hypersynchronous-HYP and low amplitude fast activity patterns-LAFA) and clinically defined SOZ. The ictogenicity (i.e., the propensity to induce the patient's habitual seizure) of a high EI node was only 44.5%. The LAFA onset pattern had a significantly higher response rate to DCS (i.e., higher evoked seizures). The concordance of an evoked habitual seizure with a clinically defined SOZ with good outcomes was over 50% (p = 0.0025). These results support targeted mapping of SOZ in LAFA onset patterns by performing DCS in high EI nodes to distinguish seizure generators (true responders) from hyperexcitable nodes that may be involved in early propagation.

Universal Germline Panel Testing for Individuals with Pheochromocytoma and Paraganglioma Produces High Diagnostic Yield

Background Practice guidelines to identify individuals with hereditary pheochromocytomas and paragangliomas (PPGLs) advocate for sequential gene testing strategy guided by specific clinical features and predate the routine use of multigene panel testing (MGPT). Objective To describe results of MGPT for hereditary PPGL in a clinically and ancestrally diverse cohort. Setting Commercial laboratory based in the United States. Methods Clinical data and test results were retrospectively reviewed in 1727 individuals who had targeted MGPT due to suspicion of hereditary PPGL from August 2013 through December 2019. Results Overall, 27.5% of individuals had a pathogenic or likely pathogenic variant (PV), 9.0% had a variant of uncertain significance, and 63.1% had a negative result. Most PVs were identified in SDHB (40.4%), followed by SDHD (21.1%), SDHA (10.1%), VHL (7.8%), SDHC (6.7%), RET (3.7%), and MAX (3.6%). PVs in FH, MEN1, NF1, SDHAF2, and TMEM127 collectively accounted for 6.5% of PVs. Clinical predictors of a PV included extra-adrenal location, early age of onset, multiple tumors, and positive family history of PPGL. Individuals with extra-adrenal PGL and a positive family history were the most likely to have a PV (85.9%). Restricting genetic testing to SDHB/C/D misses a third (32.8%) of individuals with PVs. Conclusion Our data demonstrate a high diagnostic yield in individuals with and without established risk factors, a low inconclusive result rate, and a substantial contribution to diagnostic yield from rare genes. These findings support universal testing of all individuals with PPGL and the use of concurrent MGPT as the ideal platform.

Diagnostic Value of Bronchoscopy for Peripheral Metastatic Lung Tumors

Although lungs are one of the most frequent sites of metastasis for malignant tumors, little has been reported about the value of bronchoscopy for lung metastases presenting with peripheral pulmonary lesions (PPLs). This retrospective cohort study investigated the diagnostic value of bronchoscopy for peripheral metastatic lung tumors. Consecutive patients who underwent diagnostic bronchoscopy with radial endobronchial ultrasound for PPLs and were finally diagnosed with metastatic lung tumors from April 2012 to March 2019 were included. We analyzed 235 PPLs, with a median size of 18.8 mm. The overall diagnostic yield was 76.6%. In a multivariable analysis, large lesion size (>20.0 mm vs. <20.0 mm: 87.6% vs. 67.7%, p = 0.043, OR = 2.26), inner location (inner 2/3 vs. outer 1/3: 84.8% vs. 69.1%, p = 0.004, OR = 2.79), and visibility on radiography (visible vs. invisible: 83.2% vs. 56.1%, p = 0.015, OR = 3.29) significantly affected the diagnostic yield. Although a positive bronchus sign tended to have a higher yield, no significant difference was observed (81.8% vs. 70.6%, p = 0.063). Only one case of lung abscess was observed, with no serious complications. In conclusion, bronchoscopy is a valuable technique for peripheral metastatic lung tumors, with good diagnostic accuracy and safety.

Chromosomal microarray analysis of 410 Han Chinese patients with autism spectrum disorder or unexplained intellectual disability and developmental delay

Copy number variants (CNVs) are recognized as a crucial genetic cause of neurodevelopmental disorders (NDDs). Chromosomal microarray analysis (CMA), the first-tier diagnostic test for individuals with NDDs, has been utilized to detect CNVs in clinical practice, but most reports are still from populations of European ancestry. To contribute more worldwide clinical genomics data, we investigated the genetic etiology of 410 Han Chinese patients with NDDs (151 with autism and 259 with unexplained intellectual disability (ID) and developmental delay (DD)) using CMA (Affymetrix) after G-banding karyotyping. Among all the NDD patients, 109 (26.6%) carried clinically relevant CNVs or uniparental disomies (UPDs), and 8 (2.0%) had aneuploidies (6 with trisomy 21 syndrome, 1 with 47,XXY, 1 with 47,XYY). In total, we found 129 clinically relevant CNVs and UPDs, including 32 CNVs in 30 ASD patients, and 92 CNVs and 5 UPDs in 79 ID/DD cases. When excluding the eight patients with aneuploidies, the diagnostic yield of pathogenic and likely pathogenic CNVs and UPDs was 20.9% for all NDDs (84/402), 3.3% in ASD (5/151), and 31.5% in ID/DD (79/251). When aneuploidies were included, the diagnostic yield increased to 22.4% for all NDDs (92/410), and 33.6% for ID/DD (87/259). We identified a de novo CNV in 14.9% (60/402) of subjects with NDDs. Interestingly, a higher diagnostic yield was observed in females (31.3%, 40/128) compared to males (16.1%, 44/274) for all NDDs (P = 4.8 × 10−4), suggesting that a female protective mechanism exists for deleterious CNVs and UPDs.

Using synthetic chromosome controls to evaluate the sequencing of difficult regions within the human genome

Background Next-generation sequencing (NGS) can identify mutations in the human genome that cause disease and has been widely adopted in clinical diagnosis. However, the human genome contains many polymorphic, low-complexity, and repetitive regions that are difficult to sequence and analyze. Despite their difficulty, these regions include many clinically important sequences that can inform the treatment of human diseases and improve the diagnostic yield of NGS. Results To evaluate the accuracy by which these difficult regions are analyzed with NGS, we built an in silico decoy chromosome, along with corresponding synthetic DNA reference controls, that encode difficult and clinically important human genome regions, including repeats, microsatellites, HLA genes, and immune receptors. These controls provide a known ground-truth reference against which to measure the performance of diverse sequencing technologies, reagents, and bioinformatic tools. Using this approach, we provide a comprehensive evaluation of short- and long-read sequencing instruments, library preparation methods, and software tools and identify the errors and systematic bias that confound our resolution of these remaining difficult regions. Conclusions This study provides an analytical validation of diagnosis using NGS in difficult regions of the human genome and highlights the challenges that remain to resolve these difficult regions.

Migraine in the Emergency Department: A Prospective Multinational Study of Patient Characteristics, Management, and Outcomes

<b><i>Background and Aim:</i></b> Migraine headache is commonly diagnosed in emergency departments (ED). There is relatively little real-world information about the epidemiology, investigation, management, adherence to therapeutic guidelines and disposition of patients treated in ED with a final diagnosis of migraine. The primary aim of the current study is to get a snapshot of assessment and management patterns of acute migraine presentations to the different settings of EDs with a view to raise awareness. <b><i>Methods:</i></b> This is a planned sub-study of a prospective study conducted in 67 health services in 10 countries including Australia, New Zealand, Southeast Asia, Europe, and the UK investigating the epidemiology and outcome of adult patients presenting to ED with nontraumatic headache. Outcomes of interest for this study are demographics, clinical features (including severity), patterns of investigation, treatment, disposition, and outcome of patients diagnosed as having migraine as their final ED diagnosis. <b><i>Results:</i></b> The cohort comprises 1,101 patients with a mean age of 39 years (SD ± 13.5; 73.7% [811]) were female. Most patients had had migraine diagnosed previously (77.7%). Neuroimaging was performed in 25.9% with a very low diagnostic yield or significant findings (0.07%). Treatment of mild migraine was in accordance with current guidelines, but few patients with moderate or severe symptoms received recommended treatment. Paracetamol (46.3%) and nonsteroidal anti-inflammatory drugs (42.7%) were the most commonly prescribed agents. Metoclopramide (22.8%), ondansetron (19.2%), chlorpromazine (12.8%), and prochlorperazine (12.8%) were also used. <b><i>Conclusions:</i></b> This study suggests that therapeutic practices are not congruent with current guidelines, especially for patients with severe symptoms. Efforts to improve and sustain compliance with existing management best practices are required.

Beyond Brca1/2: Homologous Recombination Repair Genetic Profile in a Large Cohort of Apulian Ovarian Cancers

Background: Pathogenic variants in homologous recombination repair (HRR) genes other than BRCA1/2 have been associated with a high risk of ovarian cancer (OC). In current clinical practice, genetic testing is generally limited to BRCA1/2. Herein, we investigated the mutational status of both BRCA1/2 and 5 HRR genes in 69 unselected OC, evaluating the advantage of multigene panel testing in everyday clinical practice. Methods: We analyzed 69 epithelial OC samples using an NGS custom multigene panel of the 5 HRR pathways genes, beyond the genetic screening routine of BRCA1/2 testing. Results: Overall, 19 pathogenic variants (27.5%) were detected. The majority (21.7%) of patients displayed a deleterious mutation in BRCA1/2, whereas 5.8% harbored a pathogenic variant in one of the HRR genes. Additionally, there were 14 (20.3%) uncertain significant variants (VUS). The assessment of germline mutational status showed that a small number of variants (five) were not detected in the corresponding blood sample. Notably, we detected one BRIP1 and four BRCA1/2 deleterious variants in the low-grade serous and endometrioid histology OC, respectively. Conclusion: We demonstrate that using a multigene panel beyond BRCA1/2 improves the diagnostic yield in OC testing, and it could produce clinically relevant results.

Percutaneous CT-Guided Biopsy of the Craniovertebral Junction: Safety, Diagnostic Yield, and Technical Notes

The craniovertebral junction defined as the occiput, the atlas, and the axis is a complex bony region that contains vital neural and vascular structures. We report the experience of a single academic institution regarding CT-guided biopsy of this skeletal region. We reviewed all of the CT-guided biopsies performed in our department, completed in the craniovertebral junction. We collected data in regard to biopsy procedures, patients’ vital statistics, and histopathological diagnosis. In total, 16 patients (8M and 8F; mean age 52; range 16–86 years old) were included in this series. In eight patients, the lesions were located in the atlas vertebra (8/16—50%), in six patients in the axis (37.5%), and in two patients in the occiput (12.5%). No complications were observed during or after the procedures. All of the procedures were technically successful. The biopsy was diagnostic in 13/16 patients (81.3%): four metastatic lesions (25%—three breast and one prostate cancers), four multiple myeloma bone lesions (25%), three aneurismal bone cysts (18.8%), one aggressive hemangioma (6.3%), and one pseudogout (6.3%). Moreover, in two-thirds (66.6%) of non-diagnostic histological reports, malignancies were excluded. CT-guided percutaneous biopsy is a safe tool and allows obtaining a histological diagnosis, in most cases, even in the most delicate site of the human skeleton—the craniovertebral junction.

Diagnosis of Genetic White Matter Disorders by Singleton Whole-Exome and Genome Sequencing Using Interactome-Driven Prioritization

Background and Objectives:Genetic white matter disorders (GWMD) are of heterogeneous origin, with more than a hundred causal genes identified to date. Classical targeted approaches achieve a molecular diagnosis in only half of all patients. Here we aim to determine the clinical utility of singleton whole-exome sequencing and whole-genome sequencing (sWES-WGS) interpreted with a phenotype- and interactome-driven prioritization algorithm to diagnose GWMD patients, while identifying novel phenotypes and candidate genes.Methods:A case series of patients of all ages with undiagnosed GWMD despite extensive standard-of-care paraclinical studies were recruited between April 2017 and December 2019 in a collaborative study at the Bellvitge Biomedical Research Institute (IDIBELL) and neurology units of tertiary Spanish hospitals. We ran sWES and WGS and applied our interactome-prioritization algorithm, based on the network expansion of a seed group of GWMD-related genes, derived from the HPO terms of each patient.Results:We received 126 patients (101 children and 25 adults), with ages ranging from 1 month to 74 years. We obtained a first molecular diagnosis by singleton WES in 59% of cases, which increased to 68% after annual reanalysis and reached 72% after WGS was performed in 16 of the remaining negative cases. We identified variants in 57 different genes among 91 diagnosed cases, with the most frequent being RNASEH2B, EIF2B5, POLR3A and PLP1; and a dual diagnosis underlying complex phenotypes in six families, underscoring the importance of genomic analysis to solve these cases. Finally, we discovered 9 candidate genes causing novel diseases, and propose additional putative novel candidate genes for yet-to-be discovered GWMD.Discussion:Our strategy enables a high diagnostic yield and is a good alternative to trio WES/WGS for GWMD. It shortens the time to diagnosis compared to the classical targeted approach, thus optimizing appropriate management. Furthermore, the interactome-driven prioritization pipeline enables the discovery of novel disease-causing genes and phenotypes, and predicts novel putative candidate genes, shedding light on etiopathogenic mechanisms that are pivotal for myelin generation and maintenance.