Biology subjects

Lee, S.

Publications and source records attributed to Lee, S..

At least 685 records · Page 38Linked to original sources

bioRxiv2019

The Ras family members follow the blood progesterone level during formation and regression in bovine corpus luteum

Ras family members regulate cellular differentiation, proliferation and survival. CL formation and regression are regulated by the blood P4 level. This study investigated the association between changes in Ras family members and the serum P4 level and determined protein interactions among Ras family members, hormone receptors, and angiogenetic and apoptotic factors during formation and regression of the bovine CL. RASAL3 and RASA3 were found using proteomics in CL and were significantly increased in the SPCL compared to the PPCL, whereas RasGEF1B was decreased in the PPCL. Hormone receptors and angiogenetic proteins expression was lower in the PPCL and SPCL than that in the RPCL, but apoptotic proteins were increased in the RPCL. The P4 and estrogen receptors positive correlated with RasGEF1B, R-Ras, and H-Ras through VEGFA, VEGFR2 and Tie2 in STRING database. RasGAP, H-Ras and R-Ras protein expression was increased in the PPCL compared to that in the SPCL, whereas RasGEF expression was decreased. In summary, Ras activation and angiogenesis in the CL were positively correlated with the blood P4 during estrous cylce. These results may increase understanding of Ras biological functions following stimulation of hormones and their receptors during tissue proliferation and degeneration.

cell biology↗

bioRxiv2019

Oral prescription opioid-seeking behavior in male and female mice

A significant portion of prescription opioid users self-administer orally rather than intravenously. Animal models of opioid addiction have demonstrated that intravenous cues are sufficient to cause drug-seeking. However, intravenous models may not model oral users, and the preference to self-administer orally appears to be partially influenced by the users sex. Our objectives were to determine whether oral opioid-associated cues are sufficient for relapse and whether sex differences exist in relapse susceptibility. Mice orally self-administered escalating doses of oxycodone under postprandial (prefed) or non-postprandial (no prefeeding) conditions. Both sexes demonstrated robust cue-induced reinstatement. In separate mice we found that oral oxycodone cues were sufficient to reinstate extinguished oral oxycodone-seeking behavior in the absence of postprandial or prior water self-administration training. During self-administration, we found that female mice earned significantly more mg/kg oxycodone than male mice. Follow-up studies indicated sex differences in psychomotor stimulation and plasma oxycodone/oxymorphone following oral oxycodone administration. In addition, gonadal steroid studies were performed in which we found divergent responses where ovariectomy enhanced and orchiectomy suppressed oral self-administration. While the suppressive effects of orchiectomy were identified across doses and postprandial conditions, the enhancing effects of ovariectomy were selective to non-postprandial conditions. These studies establish that 1) oral drug cues are sufficient to cause reinstatement that is independent of prandial conditions and water-seeking behavior, 2) earned oral oxycodone is larger in female mice compared with male mice potentially through differences in psychomotor stimulation and drug metabolism, and 3) gonadectomy produces divergent effects on oral oxycodone self-administration between sexes.

neuroscience↗

bioRxiv2019

Medroxyprogesterone reverses tolerable dose metformin-induced inhibition of invasion via matrix metallopeptidase-9 and transforming growth factor-β1 in KLE endometrial cancer cells

This study was performed to evaluate the anticancer effects of tolerable doses of metformin with or without medroxyprogesterone (MPA) in endometrial cancer cells. Cell viability, cell invasion, and levels of matrix metallopeptidase (MMP) and transforming growth factor (TGF)-{beta}1 were analyzed using three human endometrial adenocarcinoma cell lines (Ishikawa, KLE, and USPC) after treatment with different dose combinations of MPA (0, 10 M) and metformin (0, 100, 1000 M). Combining metformin (0, 100, 1000 M) and 10 M MPA induced significantly decreased cell viability in a time- and dose-dependent manner in Ishikawa cells, but not in KLE and USPC cells. There was no dose- or time-dependent cell growth inhibition, or positive western blot results for the expression of progesterone receptors and phospho-AMPKa, following treatment with any combination of metformin (0, 100, 1000 M) and 10 M MPA in KLE and USPC cells. In KLE cells, metformin treatment alone significantly inhibited cell invasion in a dose-dependent manner (1.31{+/-}0.05, 0.94{+/-}0.04, 0.83{+/-}0.05 at 0, 100 M, 1000 M, respectively; p<0.0005). The inhibitory effect of metformin was reversed to create a stimulating effect when metformin was combined with 10 M MPA (1.10{+/-}0.05, 1.42{+/-}0.18, 1.41{+/-}0.26 at 0, 100, 1000 M, respectively; p<0.005). MMP-9 and TGF-{beta}1 showed similar trends in terms of cell invasion in KLE cells. In conclusion, the anti-invasive effect of metformin in KLE cells was completely reversed to the state of no treatment by the addition of MPA; this might be mediated through MMP-9 and TGF-{beta}1. Our study suggests the possibility of these combinations doing harm, rather than good, under some conditions.

cancer biology↗

bioRxiv2019

Meta-MultiSKAT: Multiple phenotype meta-analysis for region-based association test

The power of genetic association analyses can be increased by jointly meta-analyzing multiple correlated phenotypes. Here, we develop a meta-analysis framework, Meta-MultiSKAT, that uses summary statistics to test for association between multiple continuous phenotypes and variants in a region of interest. Our approach models the heterogeneity of effects between studies through a kernel matrix and performs a variance component test for association. Using a genotype kernel, our approach can test for rare-variants and the combined effects of both common and rare-variants. To achieve robust power, within Meta-MultiSKAT, we developed fast and accurate omnibus tests combining different models of genetic effects, functional genomic annotations, multiple correlated phenotypes and heterogeneity across studies. Additionally, Meta-MultiSKAT accommodates situations where studies do not share exactly the same set of phenotypes or have differing correlation patterns among the phenotypes. Simulation studies confirm that Meta-MultiSKAT can maintain type-I error rate at exome-wide level of 2.5x10-6. Further simulations under different models of association show that Meta-MultiSKAT can improve power of detection from 23% to 38% on average over single phenotype-based meta-analysis approaches. We demonstrate the utility and improved power of Meta-MultiSKAT in the meta-analyses of four white blood cell subtype traits from the Michigan Genomics Initiative (MGI) and SardiNIA studies.

genetics↗

bioRxiv2019

Modeling mechanisms of tremor reduction for essential tremor using symmetric biphasic DBS

Essential tremor (ET) is the most common movement disorder, in which the primary symptom is a prominent, involuntary 4-10 Hz movement. For severe, medication refractory cases, deep brain stimulation (DBS) targeting the ventral intermediate nucleus of the thalamus (VIM) can be an effective treatment for cessation of tremor and is thought to work in part by disrupting tremor frequency oscillations (TFOs) in VIM. However, DBS is not universally effective and may be further disrupting cerebellar-mediated activity in the VIM. Here, we applied biophysically detailed computational modeling to investigate whether the efficacy of DBS is affected by the mechanism of generation of TFOs or by the pattern of stimulation. We simulated the effects of DBS using standard, asymmetric pulses as well as biphasic, symmetric pulses to understand biophysical mechanisms of how DBS disrupts TFOs generated either extrinsically or intrinsically. The model results suggested that the efficacy of DBS in the VIM is affected by the mechanism of generation of TFOs. Symmetric biphasic DBS reduced TFOs more than standard DBS in both networks, and these effects were stronger in the intrinsic network. For intrinsic tremor frequency activity, symmetric biphasic DBS was more effective at reducing TFOs. Simulated non-tremor signals were also transmitted during symmetric biphasic DBS, suggesting that this type of DBS may help to reduce side effects caused by disruption of the cerebellothalamocortical pathway. Biophysical details in the model provided a mechanistic interpretation of the cellular and network dynamics contributing to these effects that can be empirically tested in future studies.\n\nSignificance StatementEssential tremor (ET) is a common movement disorder, whose primary symptom is an involuntary rhythmic movement of the limbs or head. An area of the human tha-lamus demonstrates electrical activity that oscillates at the frequencies of tremor, and deep brain stimulation (DBS) in this area can reduce tremor. It is not fully understood how DBS affects tremor frequency activity in the thalamus, and studying different patterns of DBS stimulation may help to clarify these mechanisms. We created a computational model of different shapes of DBS and studied how they reduce different hypothesized generators of tremor frequency activity. A greater understanding of how DBS affects the thalamus may lead to improved treatments to reduce tremor and alleviate side effects in patients with ET.

neuroscience↗

bioRxiv2019

Scalable generalized linear mixed model for region-based association tests in large biobanks and cohorts

With very large sample sizes, population-based cohorts and biobanks provide an exciting opportunity to identify genetic components of complex traits. To analyze rare variants, gene or region-based multiple variant aggregate tests are commonly used to increase association test power. However, due to the substantial computation cost, existing region-based rare variant tests cannot analyze hundreds of thousands of samples while accounting for confounders, such as population stratification and sample relatedness. Here we propose a scalable generalized mixed model region-based association test that can handle large sample sizes and accounts for unbalanced case-control ratios for binary traits. This method, SAIGE-GENE, utilizes state-of-the-art optimization strategies to reduce computational and memory cost, and hence is applicable to exome-wide and genome-wide region-based analysis for hundreds of thousands of samples. Through the analysis of the HUNT study of 69,716 Norwegian samples and the UK Biobank data of 408,910 White British samples, we show that SAIGE-GENE can efficiently analyze large sample data (N > 400,000) with type I error rates well controlled.

genetics↗

bioRxiv2019

3D rotational motion of an endocytic vesicle on a complex microtubule network in a living cell

The transport dynamics of endocytic vesicles in a living cell contains essential biomedical information. Although the movement mechanism of a vesicle by motor proteins has been revealed, understanding the precise movement of vesicles on the cytoskeleton in a living cell has been considered challenging, due to the complex 3D network of cytoskeletons. Here, we specify the shape of the 3D interaction between the vesicle and microtubule, based on the theoretically estimated location of the microtubule and the vesicle trajectory data acquired at high spatial and temporal precision. We detected that vesicles showed more frequent direction changes with either in very acute or in obtuse angles than right angles, on similar time scales in a microtubule network. Interestingly, when a vesicle interacted with a relatively longer (> 400 nm) microtubule filament, rotational movement along the axis of the microtubule was frequently observed, implying an obstacle-avoiding motion. Our results are expected to give in-depth insight into understanding the actual 3D interactions between the intracellular molecule and complex cytoskeletal network.

biophysics↗

bioRxiv2019

Complex interaction networks of cytokines after transarterial chemotherapy in patients with hepatocellular carcinoma

Inflammation in the tumor microenvironment influences all stages of HCC development and progression as well as the anti-cancer response by immune system. In this study, we studied cytokine networks before and after transarterial chemotherapy (TACE). Serum samples obtained from 203 HCC patients treated with TACE were analyzed for inflammatory cytokines including interleukin (IL)-1{beta}, IL-2, IL-4, IL-5, IL-6, IL-9, IL-10, IL-12, IL-13, IL-17, IL-22, TNF-, IFN-{gamma}, and C-reactive protein (CRP) levels. Cytokine concentrations were measured at day 0 (D0, baseline), day3 (D3), day7 (D7), and day 60 (D60) after TACE. Network analysis revealed that modules within cytokine network at D0 were lost by D60 and modularity value (Mc) was decreased from 0.177 at D0 to -0.091 at D60. D60 had the lowest network heterogeneity and lower diameter, clustering coefficient, network density and recruited nodes. Degree correlation revealed that assortative network turned to disassortative network by D60 indicating that the network gained scale free feature. CRP, IL-2 were components of modules related with adverse outcome and IL-13, favorable outcome. Median survival month of patient group with high and low values with P-values were as follows: D0 CRP, 9.5 month (M), 54.2M (P<0.0001); D0 IL-2, 39.9M, 56.1M (P=0.0084); D3 CRP, 31.3M, 55.1 M (P=0.0056); D7 CRP, 28.7M, 50.7M (P=0.0065); IL-13, 51.9M, 33.6M (P=0.06). Network modularity decreased with temporal changes. Components of modules that included CRP, IL-2 and IL-6 were associated with adverse outcome and short overall survival. These modules were dissolved by D60 after TACE. Degree correlation decreased by D60, indicating that the cytokine network gained the scale free network property as in other biological network. TACE treatment converted cytokine network from that with inflammatory module to that with scale free network feature and without modules. Further studies are required to verify temporal changes of cytokine network in HCC patients after TACE.

immunology↗

bioRxiv2019

Single cell ATAC-seq identifies broad changes in neuronal abundance and chromatin accessibility in Down Syndrome

Down Syndrome (DS) is caused by triplication of chr21 and is associated with cognitive impairment, Alzheimers Disease, and other developmental alterations. The Ts65Dn mouse model for DS has triplication of sequences syntenic with human chr21, and traits resembling those seen in humans with DS. We performed single-cell combinatorial indexing assay for transposase accessible chromatin using sequencing (sci-ATAC-seq) on cortices of adult Ts65Dn mice and control littermates. Analyses of 13,766 cells revealed 26 classes of cells. The most abundant class of excitatory neurons was reduced by 17% in Ts65Dn mice, and three of the four most common classes of interneurons were increased by 50%. Ts65Dn mice display changes in accessibility at binding motifs for transcription factors that are determinants of neuronal lineage, and others encoded within triplicated regions. These studies define previously uncharacterized cellular and molecular features of DS, and potential mechanisms underlying the condition.

genomics↗

bioRxiv2019

Machine Learning Methods to Identify Genetic Correlates of Radiation-Associated Contralateral Breast Cancer in the WECARE Study

The purpose of this study is to identify germline single nucleotide polymorphisms (SNPs) that optimally predict radiation-associated contralateral breast cancer (RCBC) and to provide new biological insights into the carcinogenic process. Fifty-two women with contralateral breast cancer and 153 women with unilateral breast cancer were identified within the Womens Environmental Cancer and Radiation Epidemiology (WECARE) Study who were at increased risk of RCBC because they were [≤] 40 years of age at first diagnosis of breast cancer and received a scatter radiation dose > 1 Gy to the contralateral breast. A previously reported algorithm, preconditioned random forest regression, was applied to predict the risk of developing RCBC. The resulting model produced an area under the curve of 0.62 (p=0.04) on hold-out validation data. The biological analysis identified the cyclic AMP-mediated signaling and Ephrin-A as significant biological correlates, which were previously shown to influence cell survival after radiation in an ATM-dependent manner. The key connected genes and proteins that are identified in this analysis were previously identified as relevant to breast cancer, radiation response, or both. In summary, machine learning/bioinformatics methods applied to genome-wide genotyping data have great potential to reveal plausible biological correlates associated with the risk of RCBC.

bioinformatics↗

bioRxiv2019

Immune gene expression profiling reveals heterogeneity in luminal breast tumors

Disease heterogeneity of immune gene expression patterns of luminal breast cancer (BC) has not been well studied. We performed immune gene expression profiling of tumor and adjacent normal tissue in 92 Asian luminal BC patients and identified three distinct immune subtypes. Tumors in one subtype exhibited signs of T-cell activation, lower ESR1/ESR2 expression ratio and higher expression of immune checkpoint genes, nonsynonymous mutation burden, APOBEC-signature mutations, and increasing body mass index compared to other luminal tumors. Tumors in a second subtype were characterized by increased expression of interferon-stimulated genes and enrichment for TP53 somatic mutations. The presence of three immune subtypes within luminal BC was replicated in cases drawn from The Cancer Genome Atlas and a Korean breast cancer study. Our findings suggest that immune gene expression and associated genomic features could be useful to further stratify luminal BC beyond the current luminal A/B classification.

genomics↗

bioRxiv2019

Nedd4 E3 ligase and beta-arrestins regulate ubiquitination, trafficking, and stability of the mGlu7 receptor

The metabotropic glutamate receptor 7 (mGlu7) is a class C G protein-coupled receptor (GPCR) that modulates excitatory neurotransmitter release at the presynaptic active zone. Although post-translational modification of cellular proteins with ubiquitin is a key molecular mechanism governing protein degradation and function, mGlu7 ubiquitination and its functional consequences have not been elucidated yet. Here, we report that Nedd4 ubiquitin E3 ligase and {beta}-arrestins regulate ubiquitination of mGlu7 in heterologous cells and neurons. Upon agonist-stimulation, {beta}-arrestins recruit Nedd4 to mGlu7 and facilitate Nedd4-mediated ubiquitination of mGlu7. Nedd4 and {beta}-arrestins regulate constitutive and agonist-induced endocytosis of mGlu7 and are required for mGlu7-dependent MAPK signaling in neurons. In addition, Nedd4-mediated ubiquitination results in the degradation of mGlu7 by both the lysosomal and proteasomal degradation pathways. These findings provide a model in which Nedd4 and {beta}-arrestin act together as a complex to regulate mGlu7 surface expression and function at the presynaptic terminals.

neuroscience↗

bioRxiv2019

Sarcopenia is an independent predictor of hospitalization in chronic kidney disease outpatients

BackgroundPatients with chronic kidney disease (CKD) experience much more marked and earlier muscle wasting than subjects who do not have chronic illnesses. However, a few studies that have examined sarcopenia have been reported in CKD patients. We investigated the prevalence of sarcopenia in predialysis and dialysis outpatients with CKD and explored its relationship with the clinical outcomes.\n\nMeasurementsSarcopenia was defined as reduced muscle strength accompanied by decreased adjusted appendicular skeletal muscle (ASM), while those patients who exhibited only one of these characteristics were categorized as presarcopenic patients. ASM was measured by bioimpedence analysis, and muscle strength was evaluated by handgrips. ASM was adjusted by weight (ASM/wt). Patients were prospectively followed for up to 2 years.\n\nResultsOne hundred seventy-nine patients were recruited (114 male and 65 female patients who were classified into 103 predialysis patients and 76 dialysis patients, with 44.7% having diabetes). Their mean age was 60.6 {+/-} 13.5 years old. The prevalence of sarcopenia was 9.5%, while 55.9% of the patients were categorized as presarcopenic. The ASM/wt index showed significant correlations with age, handgrip strength, HOMA-IR and frailty scores. Multivariate Cox proportional hazards models demonstrated that the risk of hospitalization was significantly higher for patients with presarcopenia [hazard ratio (HR), 2.48; 95% confidence interval (CI), 1.180-5.230], and the risk of hospitalization was much higher for patients with sarcopenia than for patients in the nonsarcopenic group (HR, 9.11; 95% CI, 2.295-25.182)\n\nConclusionsSarcopenia and presarcopenia, which were defined using the ASM/wt index and handgrip strength, predicted a poorer, hospitalization-free survival in CKD patients

scientific communication and education↗

bioRxiv2018

Genomic perspectives on adaptation and conservation in the endangered long-tailed goral (Naemorhedus caudatus).

Native to the mountains of East Asia, the long-tailed goral (Naemorhedus caudatus) is a vulnerable wild ungulate in the tribe Caprini. To understand key conservation issues related to fragmentation and subsequent endangerment of this montane species, we sequenced and analyzed the genome of a long-tailed goral to explore historical demography, contemporary levels of genetic diversity, and potential immune response. When compared to ten additional mammalian reference genomes, we identified 357 positively selected genes (PSGs) in the long-tailed goral and 364 PSGs in the Caprini lineage. Gene Ontology analyses showed statistical enrichment in biological processes related to immune function and in genes and pathways related to blood coagulation. We also identified low levels of heterozygosity (0.00114) in the long-tailed goral along with decreases in population size relative to other species of Caprini. Finally, we provide evidence for positive selection on the muscle development gene myostatin (MSTN) in the Caprini lineage, which may have increased the muscle development and climbing ability in the caprine common ancestor. Low effective population size and decreased heterozygosity of the long-tailed goral raise conservation concern about the effects of habitat fragmentation, over harvest, and inbreeding on this vulnerable species.

bioinformatics↗

bioRxiv2018

Somatic uniparental disomy with a rare EFL1 variant causes Shwachman-Diamond syndrome through dysregulating ribosomal protein synthesis

Shwachman-Diamond syndrome (SDS; OMIM: #260400) is caused by variants in SBDS (Shwachman-Bodian-Diamond syndrome gene), which encodes a protein that plays an important role in ribosome assembly. Recent reports suggest that recessive variants in EFL1 are also responsible for SDS. However, the precise genetic mechanism that leads to EFL1-induced SDS remains incompletely understood. Here we present three unrelated Korean SDS patients that carry biallelic pathogenic variants in EFL1 with biased allele frequencies, resulting from a bone marrow-specific somatic uniparental disomy (UPD) in chromosome 15. The recombination events generated cells that were homozygous for the relatively milder variant, allowing for the evasion of catastrophic physiological consequences. Still, the milder EFL1 variant was solely able to impair 80S ribosome assembly and induce SDS features in cell line, zebrafish, and mouse models. The loss of EFL1 resulted in a pronounced inhibition of terminal oligo-pyrimidine element-containing ribosomal protein transcript 80S assembly. Therefore, we propose a more accurate pathogenesis mechanism of EFL1 dysfunction that eventually leads to aberrant translational control and ribosomopathy.

genetics↗

bioRxiv2018

Real-time monitoring of bacterial growth and fast antimicrobial susceptibility tests exploiting multiple light scattering

AbstractAntimicrobial susceptibility test (AST) is widely used to provide the minimum inhibitory concentration of bacteria, and crucial to provide appropriate uses of antibiotics and to address the issue of drug-resistance bacteria. However, ASTs require the time-consuming incubation about 16-20 h for the visual determination of the growth of bacterial colonies, which has been a major obstacle to on-site applications of ASTs. In this study, we propose a rapid and non-invasive method based on laser speckles to evaluate the bacterial growth movements in real time, thus reducing the time for the agar dilution method. With a simple configuration compatible with conventional agar plates, the analysis of laser speckle from samples enables the early detection of the presence of growth as well as its detailed history of the colony-forming movement on agar plates. Using the samples prepared through the same procedure as the agar dilution method, we obtained the AST results at least 4-8 hours earlier than the conventional method without compromising the accuracy. This technique does not require for the use of exogenous agents, but works for most bacteria regardless of their species. Furthermore, the distinctive responses of several species to microbial agents were revealed through the present technique supporting a comprehensive analysis of the effect of the antibiotics. The findings suggest that this new method could be a useful tool for rapid, simple, and low-cost ASTs in addition to providing the historical information of the bacterial growth on agar plates.

microbiology↗

bioRxiv2018

3D brain angiogenesis model to reconstitute maturation of functional human blood-brain barrier in vitro

0.Human central nervous system (CNS) vasculature in brain expresses a distinctive barrier phenotype, the blood-brain barrier (BBB), which protects the brain against harmful pathogens. Since the BBB contributes to low success rate in CNS pharmacotherapy by restricting drug transportation, the development of an in vitro human BBB model has been in demand. Previous models were unable to fully represent the complex threedimensional (3D) anatomical structure or specific barrier phenotypes of the matured BBB. In this study, we present a physiological 3D microfluidic model of the human BBB that mimics its developmental process including CNS angiogenesis and subsequent maturation in concert with perivascular cells. We used microfluidic hydrogel patterning to precisely and sequentially load perivascular cells into the model, investigate the role of each cell type on BBB phenotypes. We confirmed the necessity of the tri-culture system (brain endothelium with pericytes and astrocytes) to attain the characteristic BBB vascular morphology such as minimized diameter and maximized junction expression. In addition, endothelial-perivascular cell interaction was also critical in reconstituting p-glycoprotein (p-gp), efflux transporter in our model that works as metabolic barrier of BBB and blocks drug to enter CNS. The 3D hydrogel matrix was tuned with hyaluronic acid (HA) to optimize the interaction between endothelial cells and astrocytes. Our in vitro BBB system mimics CNS angiogenesis and characteristic features of BBB. We expect the model will contribute to deeper understanding of neurodegenerative diseases and cost-efficient development of effective CNS medications.

bioengineering↗

bioRxiv2018

Comprehensive genetic analysis by whole exome sequencing in 352 Korean pediatric patients with unknown neurodevelopmental disorders

ImportanceAccurate diagnosis of pediatric patients with complicated neurological problems demands a well-coordinated combination of robust genetic analytic capability and delicate clinical evaluation. It should be tested whether this challenge can be augmented by whole exome sequencing (WES).\n\nObjectiveTo evaluate the utility of WES-based diagnosis and discovery of novel variants of undiagnosed patients with complex neurodevelopmental problems in a country with a centralized medical system.\n\nDesign, setting, and participantsA cohort of 352 Korean patients, believed to cover a major portion of the entire country from July 2014 to April 2017, with a broad spectrum of neurodevelopmental disorders without any pathogenic variants revealed by conventional methods were evaluated by trio-based WES at Seoul National University Childrens Hospital.\n\nExposuresWES of patients and parents and subsequent evaluation of genetic variants.\n\nMain outcomes and measuresGenetic variants from each patient were evaluated for known disease association and novel variants were assessed for possible involvement with neurodevelopment process.\n\nResultsWe identified disease-causing variants, including newly discovered variants, in 57.4% of the probands, who had underwent a mean of 5.6 years of undiagnosed periods and visited mean of 2.3 tertiary hospitals. The cohort included 112 patients with variants that were previously reported as pathogenic (31.8%), 16 patients with copy number variants (4.5%) and 27 patients with variants that were associated with different clinical symptoms (7.7%). We also discovered potentially pathogenic variants from 47 patients that required further functional assessments (13.4%) and demonstrated potential implications in neurodevelopmental disorders. Following the genetic analysis, we provided more precise treatments to selected patients. A few clinical vignettes are presented that illuminate the potential diagnostic pitfalls that one could have encountered without this approach.\n\nConclusions and relevanceOur results highlight the utility of WES-based diagnosis for improved patient care in a country with a centralized medical system and discovery of novel pathophysiology mechanisms.\n\nKey pointsO_ST_ABSQuestionC_ST_ABSWhat is the advantage of whole exome sequencing based diagnosis of pediatric neurology patients with unknown rare symptoms in a large tertiary clinic in a country with a centralized medical system?\n\nFindingsWhole exome sequencing of 352 Korean patients, with a mean of 5.7 years of undiagnosed period, yielded 44.0% of conservative diagnostic yield. A number of cases were directly benefitted by trio-based WES via termination of diagnostic odyssey, genetic counseling for next offspring, or suggestion of more effective and customized treatment options.\n\nMeaningWe report on the establishment of a national-level whole exome-based diagnosis system, with emphasis on deliberate integration of clinical interpretation and genetic analysis. Whole exome sequencing should be a choice of diagnostic tools for pediatric neurologic patients with ambiguous symptoms.

genetics↗