Expanding the phenotypic spectrum of NOTCH1 variants: clinical manifestations in families with congenital heart disease.

Pathogenic variants in NOTCH1 are associated with non-syndromic congenital heart disease (CHD) and Adams-Oliver syndrome (AOS). The clinical presentation of individuals with damaging NOTCH1 variants is characterized by variable expressivity and incomplete penetrance; however, data on systematic phenotypic characterization are limited. We report the genotype and phenotype of a cohort of 33 individuals (20 females, 13 males; median age 23.4 years, range 2.5-68.3 years) from 11 families with causative NOTCH1 variants (9 inherited, 2 de novo; 9 novel), ascertained from a proband with CHD. We describe the cardiac and extracardiac anomalies identified in these 33 individuals, only four of whom met criteria for AOS. The most common CHD identified was tetralogy of Fallot, though various left- and right-sided lesions and septal defects were also present. Extracardiac anomalies identified include cutis aplasia (5/33), cutaneous vascular anomalies (7/33), vascular anomalies of the central nervous system (2/10), Poland anomaly (1/33), pulmonary hypertension (2/33), and structural brain anomalies (3/14). Identification of these findings in a cardiac proband cohort supports NOTCH1-associated CHD and NOTCH1-associated AOS lying on a phenotypic continuum. Our findings also support (1) Broad indications for NOTCH1 molecular testing (any familial CHD, simplex tetralogy of Fallot or hypoplastic left heart); (2) Cascade testing in all at-risk relatives; and (3) A thorough physical exam, in addition to cardiac, brain (structural and vascular), abdominal, and ophthalmologic imaging, in all gene-positive individuals. This information is important for guiding the medical management of these individuals, particularly given the high prevalence of NOTCH1 variants in the CHD population.

Quality of Life in Patients With Chronic Limb-Threatening Ischemia Treated With Revascularization.

BACKGROUND: In the BEST-CLI trial (Best Endovascular Versus Best Surgical Therapy for Patients With Chronic Limb-Threatening Ischemia), a prespecified secondary objective was to assess the effects of revascularization strategy on health-related quality of life (HRQoL). METHODS: Patients with chronic limb-threatening ischemia were randomized to surgical bypass (Bypass) or endovascular intervention (Endo) in 2 parallel trials. Cohort 1 included patients with single-segment great saphenous vein; cohort 2 included those lacking suitable single-segment great saphenous vein. HRQoL was assessed over the trial duration using Vascular Quality-of-Life (VascuQoL), European Quality-of-Life-5D (EQ-5D), the Short Form-12 (SF-12) Physical Component Summary (SF-12 PCS), SF-12 Mental Component Summary (SF-12 MCS), Utility Index Score (SF-6D R2), and numeric rating scales of pain. HRQoL was summarized by cohort and compared within and between groups using mixed-model linear regression. RESULTS: A total of 1193 and 335 patients in cohorts 1 and 2 with a mean follow-up of 2.9 and 2.0 years, respectively, were analyzed. In cohort 1, HRQoL significantly improved from baseline to follow-up for both groups across all measures. For example, mean (SD) VascuQoL scores were 3.0 (1.3) and 3.0 (1.2) for Bypass and Endo at baseline and 4.7 (1.4) and 4.8 (1.5) over follow-up. There were significant group differences favoring Endo when assessed with VascuQoL (difference, -0.14 [95% CI, -0.25 to -0.02]; P=0.02), SF-12 MCS (difference, -1.03 [95% CI, -1.89 to -0.18]; P=0.02), SF-6D R2 (difference, -0.01 [95% CI, -0.02 to -0.001]; P=0.03), numeric rating scale pain at present (difference, 0.26 [95% CI, 0.03 to 0.49]; P=0.03), usual level during previous week (difference, 0.26 [95% CI, 0.04 to 0.48]; P=0.02), and worst level during previous week (difference, 0.29 [95% CI, 0.02 to 0.56]; P=0.04). There was no difference between treatment arms on the basis of EQ-5D (difference, -0.01 [95% CI, -0.03 to 0.004]; P=0.12) or SF-12 PCS (difference, -0.41 [95% CI, -1.2 to 0.37]; P=0.31). In cohort 2, HRQoL also significantly improved from baseline to the end of follow-up for both groups based on all measures, but there were no differences between Bypass and Endo on any measure. CONCLUSIONS: Among patients with chronic limb-threatening ischemia deemed eligible for either Bypass or Endo, revascularization resulted in significant and clinically meaningful improvements in HRQoL. In patients with an available single-segment great saphenous vein for bypass, but not among those without one, Endo was statistically superior on some HRQoL measures; however, these differences were below the threshold of clinically meaningful difference.

Role of comprehensive cytogenomic investigation in successful reproductive outcome of parental small neocentromeric supernumerary ring chromosome: A case report.

Small supernumerary marker chromosomes (sSMC) can form small supernumerary ring chromosomes (sSRC). Loss of parentally inherited sSRC containing vital gene content may cause an "unbalanced" karyotype and fetal microdeletion syndromes. Rarely, sSRC with neocentromere can be inherited, leading to a "balanced" karyotype, which can be diagnosed with preimplantation genetic testing.

Challenges experienced by genetic counselors while they provided counseling about mosaic embryos.

Objective: To survey genetic counselors (GCs) who have counseled about mosaic embryos regarding the challenges they faced in counseling this patient population and assess their need for more resources to support their practice. Design: Self-administered online survey. Setting: Academic university. Study Population: Seventy-eight GCs primarily from the United States and Canada. Interventions: Genetic counselors completed a quantitative survey with an embedded qualitative component. Quantitative data were analyzed by descriptive statistics. An inductive thematic analysis was performed on open-text responses. Main Outcome Measures: Genetic counselors were asked what clinical activities relating to mosaic embryos they performed. They were then asked to rate how challenging each activity was to perform using a 5-point scale; a rating of 4 or 5 was defined as highly challenging. Open-text questions enabled GCs to describe factors that they felt contributed to these challenges. Results: The challenges reported by GCs included the uncertainty of outcomes in offspring after mosaic embryo transfer, limited guidelines available to assist clinicians with counseling about mosaic embryos, and ranking mosaic embryos by suitability for transfer. The contributing factors suggested by participants included limited outcome data, limited GC involvement in pretest counseling for preimplantation genetic testing for aneuploidy (PGT-A), and perceived inconsistency in counseling practices across clinics. Genetic counselors differed in their genetic testing recommendations for pregnancies conceived after mosaic embryo transfer. Amniocentesis and postnatal assessment were recommended by 85% and 49% of GCs, respectively, and 15% recommended chorionic villus sampling and noninvasive prenatal testing. Almost all (92%) reported a need for more resources, such as standardized guidelines, more outcome data, and continuing education on PGT-A and mosaicism. Conclusions: This study describes challenges experienced by GCs while they counseled about mosaic embryos. Our findings demonstrate a need for more outcome data on mosaic embryo pregnancies and for evidence-based clinical guidelines. The differing recommendations for prenatal genetic testing among GCs in the study warrant further research into contributing factors. We strongly recommend that pretest counseling, including a discussion regarding mosaicism, is provided to all couples considering PGT-A to reduce counseling challenges and to promote patients' informed decision-making.

Surgery or Endovascular Therapy for Chronic Limb-Threatening Ischemia.

BACKGROUND: Patients with chronic limb-threatening ischemia (CLTI) require revascularization to improve limb perfusion and thereby limit the risk of amputation. It is uncertain whether an initial strategy of endovascular therapy or surgical revascularization for CLTI is superior for improving limb outcomes. METHODS: In this international, randomized trial, we enrolled 1830 patients with CLTI and infrainguinal peripheral artery disease in two parallel-cohort trials. Patients who had a single segment of great saphenous vein that could be used for surgery were assigned to cohort 1. Patients who needed an alternative bypass conduit were assigned to cohort 2. The primary outcome was a composite of a major adverse limb event - which was defined as amputation above the ankle or a major limb reintervention (a new bypass graft or graft revision, thrombectomy, or thrombolysis) - or death from any cause. RESULTS: In cohort 1, after a median follow-up of 2.7 years, a primary-outcome event occurred in 302 of 709 patients (42.6%) in the surgical group and in 408 of 711 patients (57.4%) in the endovascular group (hazard ratio, 0.68; 95% confidence interval [CI], 0.59 to 0.79; P<0.001). In cohort 2, a primary-outcome event occurred in 83 of 194 patients (42.8%) in the surgical group and in 95 of 199 patients (47.7%) in the endovascular group (hazard ratio, 0.79; 95% CI, 0.58 to 1.06; P = 0.12) after a median follow-up of 1.6 years. The incidence of adverse events was similar in the two groups in the two cohorts. CONCLUSIONS: Among patients with CLTI who had an adequate great saphenous vein for surgical revascularization (cohort 1), the incidence of a major adverse limb event or death was significantly lower in the surgical group than in the endovascular group. Among the patients who lacked an adequate saphenous vein conduit (cohort 2), the outcomes in the two groups were similar. (Funded by the National Heart, Lung, and Blood Institute; BEST-CLI ClinicalTrials.gov number, NCT02060630.).

New cases that expand the genotypic and phenotypic spectrum of Congenital NAD Deficiency Disorder.

Nicotinamide adenine dinucleotide (NAD) is an essential coenzyme involved in over 400 cellular reactions. During embryogenesis, mammals synthesize NAD de novo from dietary l -tryptophan via the kynurenine pathway. Biallelic, inactivating variants in three genes encoding enzymes of this biosynthesis pathway (KYNU, HAAO, and NADSYN1) disrupt NAD synthesis and have been identified in patients with multiple malformations of the heart, kidney, vertebrae, and limbs; these patients have Congenital NAD Deficiency Disorder HAAO and four families with biallelic variants in KYNU. These patients present similarly with multiple malformations of the heart, kidney, vertebrae, and limbs, of variable severity. We show that each variant identified in these patients results in loss-of-function, revealed by a significant reduction in NAD levels via yeast genetic complementation assays. For the first time, missense mutations are identified as a cause of malformation and shown to disrupt enzyme function. These missense and frameshift variants cause moderate to severe NAD deficiency in yeast, analogous to insufficient synthesized NAD in patients. We hereby expand the genotypic and corresponding phenotypic spectrum of Congenital NAD Deficiency Disorder.

Heterozygous NOTCH1 deletion associated with variable congenital heart defects.

Pathogenic heterozygous variants in the NOTCH1 gene are known to be associated with both left and right-sided congenital cardiac anomalies with strikingly incomplete penetrance and variable phenotypic expressivity. De novo NOTCH1 whole gene deletion has been reported rarely in the literature and its association with cardiac defects is less well established. Here, we report four cases of NOTCH1 gene deletion from two families associated with a spectrum of congenital heart defects from bicuspid aortic valve to complex cardiac anomalies. This is the first description of a familial NOTCH1 deletion, showing apparently high penetrance, which may be unique to this mechanism of disease. Immunohistochemical staining of cardiac tissue demonstrated reduced levels of NOTCH1 expression in both the left and right ventricular outflow tracts. These cases suggest that haploinsufficiency caused by NOTCH1 gene deletion is associated with both mild and severe cardiac defects, similar to those caused by pathogenic variants in the gene, but with apparently higher, if not complete, penetrance.

The association between pre-tonsillectomy education and postoperative emergency department returns: A retrospective cohort pilot study.

INTRODUCTION: Tonsillectomy is the most common pediatric surgery in Canada. Post-tonsillectomy 30-day Emergency Department (ED) visit rates are higher than other pediatric day surgeries. To date, there have been no studies assessing whether additional preoperative education directed by Child Life Specialists impacts preventable ED visits. The primary aim of this study was to evaluate whether additional preoperative tonsillectomy education is feasible and is associated with fewer ED visits and admissions in the immediate postoperative period compared to standard care. The secondary aim of this study was to assess whether this education was associated with a lower ED visit rate for preventable causes. METHODS: This is a retrospective chart review conducted in an academic tertiary pediatric hospital. Patients undergoing tonsillectomy surgery (from 2014 to 2019) were divided into three groups: consultation with a Child Life Specialist plus educational Booklet plus traditional surgeon-led education (CLS), educational Booklet plus surgeon-led education (Booklet), and traditional surgeon-led education (Traditional). The feasibility of the CLS education was assessed and the 30-day ED visit and admission rates were compared between groups. Visits included patients who returned to ED post-tonsillectomy and were not admitted, whereas admission included those who returned to ED and were admitted. RESULTS: 2081 patients undergoing tonsillectomy were included. 329 (15.8%) presented to the ED (within a median of 5 days), and 92 (4.4%) were admitted. ED visit/admission rates by group were: 14.7%/4.4% (CLS), 15.8%/4.1% (Booklet), and 16.2%/4.7% (Traditional) (p = 0.81/p = 0.84). The most common reason for return to ED was Hemorrhage (4.9%). Patients also returned to the ED for preventable reasons such as dehydration, pain, nausea/vomitting and fevers. CONCLUSIONS: Additional preoperative tonsillectomy education is feasible but is not associated with fewer ED visits and admissions, or fewer ED visits for preventable causes. Further research is needed to identify the optimal intervention to address the high post-tonsillectomy ED visit rate.

Prenatal and preconception genetic counseling for consanguinity: Consanguineous couples' expectations, experiences, and perspectives.

Consanguinity, the union between two individuals who are related as second cousins or closer, is a long-standing and respected tradition in many communities. Although there are social and economic benefits of consanguineous unions, offspring are at increased risk of having an inherited genetic condition or congenital anomaly. Genetic counseling services for consanguinity are available to couples at many centers. However, little is known about patient expectations of and experiences with genetic counseling for this indication, or their perspectives on genetic screening relevant to family planning, such as expanded carrier screening (ECS). This exploratory qualitative study involved interviews with 13 individuals who had recently received preconception or prenatal genetic counseling for consanguinity at a single center. We sought to gain insight into their expectations for the genetic counseling session, experiences discussing family history and reproductive risks with the genetic counselor, and views on ECS. Interview transcripts were analyzed using an interpretive descriptive approach. Data analysis revealed three main themes: (a) anticipation balances apprehension before the appointment; (b) genetic counseling reduces anxiety and empowers; and (c) the need for wider information dissemination about consanguinity-related risks and genetic services. Our findings support the personal utility of genetic counseling for consanguinity and demonstrate the need for increased visibility and access to genetics information, counseling, and testing relevant to this patient population.

Design and Rationale of the Best Endovascular Versus Best Surgical Therapy for Patients With Critical Limb Ischemia (BEST-CLI) Trial.

BACKGROUND: Critical limb ischemia (CLI) is increasing in prevalence, and remains a significant source of mortality and limb loss. The decision to recommend surgical or endovascular revascularization for patients who are candidates for both varies significantly among providers and is driven more by individual preference than scientific evidence. METHODS AND RESULTS: The Best Endovascular Versus Best Surgical Therapy for Patients With Critical Limb Ischemia (BEST-CLI) Trial is a prospective, randomized, multidisciplinary, controlled, superiority trial designed to compare treatment efficacy, functional outcomes, quality of life, and cost in patients undergoing best endovascular or best open surgical revascularization. Approximately 140 clinical sites in the United States and Canada will enroll 2100 patients with CLI who are candidates for both treatment options. A pragmatic trial design requires consensus on patient eligibility by at least 2 investigators, but leaves the choice of specific procedural strategy within the assigned revascularization approach to the individual treating investigator. Patients with suitable single-segment of saphenous vein available for potential bypass will be randomized within Cohort 1 (n=1620), while patients without will be randomized within Cohort 2 (n=480). The primary efficacy end point of the trial is Major Adverse Limb Event-Free Survival. Key secondary end points include Re-intervention and Amputation-Free-Survival and Amputation Free-Survival. CONCLUSIONS: The BEST-CLI trial is the first randomized controlled trial comparing endovascular therapy to open surgical bypass in patients with CLI to be carried out in North America. This landmark comparative effectiveness trial aims to provide Level I data to clarify the appropriate role for both treatment strategies and help define an evidence-based standard of care for this challenging patient population. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov/. Unique identifier: NCT02060630.

The management of greater trochanteric pain syndrome: A systematic literature review.

Greater trochanteric pain syndrome (GTPS) is a common cause of lateral hip pain. Most cases respond to conservative treatments with a few refractory cases requiring surgical intervention. For many years, this condition was believed to be caused by trochanteric bursitis, with treatments targeting the bursitis. More recently gluteal tendinopathy/tears have been proposed as potential causes. Treatments are consequently developing to target these proposed pathologies. At present there is no defined treatment protocol for GTPS. The purpose of this systematic literature review is to evaluate the current evidence for the effectiveness of GTPS interventions, both conservative and surgical.

Neck swelling after thyroidectomy: not always a haematoma.

We present a case of a patient who returned with a neck swelling 6 days following thyroidectomy and central neck compartment lymphadenectomy for suspected thyroid carcinoma. The initial clinical suspicion pointed to a haematoma, but a needle aspiration showed chyle. Chyle leak is a rare complication of thyroid surgery. In the described case, this was successfully managed conservatively with repeated aspirations and a low-fat diet. We discuss the aetiology, presentation and management of this complication.

Morphine or Ibuprofen for post-tonsillectomy analgesia: a randomized trial.

BACKGROUND: Pediatric sleep disordered breathing is often caused by hypertrophy of the tonsils and is commonly managed by tonsillectomy. There is controversy regarding which postsurgical analgesic agents are safe and efficacious. METHODS: This prospective randomized clinical trial recruited children who had sleep disordered breathing who were scheduled for tonsillectomy +/- adenoid removal. Parents were provided with a pulse oximeter to measure oxygen saturation and apnea events the night before and the night after surgery. Children were randomized to receive acetaminophen with either 0.2-0.5 mg/kg oral morphine or 10 mg/kg of oral ibuprofen. The Objective Pain Scale and Faces Scale were used to assess effectiveness on postoperative day 1 and day 5. The primary endpoint was changes in respiratory parameters during sleep. RESULTS: A total of 91 children aged 1 to 10 years were randomized. On the first postoperative night, with respect to oxygen desaturations, 86% of children did not show improvement in the morphine group, whereas 68% of ibuprofen patients did show improvement (14% vs 68%; P < .01). The number of desaturation events increased substantially in the morphine group, with an average increase of 11.17 ± 15.02 desaturation events per hour (P < .01). There were no differences seen in analgesic effectiveness, tonsillar bleeding, or adverse drug reactions. CONCLUSIONS: Ibuprofen in combination with acetaminophen provides safe and effective analgesia in children undergoing tonsillectomy. Post-tonsillectomy morphine use should be limited, as it may be unsafe in certain children.

PGD for a carrier of an intrachromosomal insertion using aCGH.

Intrachromosomal insertions are rare and difficult to diagnose. However, making the correct diagnosis is critical for genetic risk assessment, and prenatal and preimplantation genetic diagnosis outcomes. We present a case of preimplantation genetic diagnosis (PGD) using array comparative genomic hybridization (aCGH) following trophectoderm biopsy of embryos created after in vitro fertilization for a carrier of an intrachromosomal insertion on chromosome 1 [46,XX, ins(1)(q44q23q32.1)]. The PGD analysis of 6 blastocysts demonstrated 67% unbalanced embryos. No pregnancy was achieved after the transfer of 2 euploid embryos. To the best of our knowledge, this is the first reported case of PGD using aCGH following trophectoderm biopsy for a carrier of an intrachromosomal insertion.

Unilateral vocal fold paralysis after congenital cardiothoracic surgery: a meta-analysis.

BACKGROUND AND OBJECTIVE: There is variation in the literature in regard to the occurrence of unilateral vocal fold paralysis (UVFP) after congenital cardiothoracic surgery. The objective of this study was to identify and appraise the evidence for the occurrence of UVFP after congenital cardiothoracic surgery in a meta-analysis. METHOD: A comprehensive search strategy in Medline, Embase, and the Cochrane Library was conducted, limited to English publications. Two independent reviewers screened studies for eligibility criteria. Of the 162 identified studies, 32 (20%) met the inclusion criteria. Using the Oxford Centre for Evidence-Based Medicine guidelines, 2 reviewers appraised the level of evidence, extracted data, and resolved discrepancies by consensus. Weighted pooled proportion and 95% confidence intervals (CIs) are reported. RESULTS: Thirty-two studies (n = 5625 patients) were included. Levels of evidence varied from level 3 to 4. Among all studies, the weighted pooled proportion of UVFP was 9.3% (95% CI, 6.6% to 12.5%), and among 11 studies (n = 584 patients) that postoperatively evaluated patients with flexible nasopharyngolaryngoscopy to document presence of UVFP, the weighted pooled proportion of UVFP was 29.8% (95% CI, 18.5% to 42.5%). Twenty-one studies (n = 2748 patients) evaluated patients undergoing patent ductus arteriosus ligation surgery, and the weighted pooled proportion of UVFP was 8.7% (95% CI, 5.4% to 12.6%). Six of these (n = 274 patients) assessed all patients postoperatively, and the weighted pooled proportion of UVFP was 39% (95% CI, 18% to 63%). Pooled analyses of risk factors and comorbidities are reported. Heterogeneity and publication bias were detected. CONCLUSIONS: UVFP is a demonstrated risk of congenital cardiothoracic surgery. Routine postoperative nasopharyngolaryngoscopy for vocal fold assessment by an otolaryngologist is suggested.

Roll-in experience from the Cardiovascular Outcomes with Renal Atherosclerotic Lesions (CORAL) study.

PURPOSE: To describe the experience and results from the roll-in phase of the Cardiovascular Outcomes with Renal Atherosclerotic Lesions (CORAL) study. MATERIALS AND METHODS: The CORAL roll-in database was used to describe the baseline characteristics of the patients in the roll-in cohort, all of whom underwent renal artery stent placement; to evaluate CORAL site performance; to compare estimates of lesion (stenosis) severity made by site interventionalists with the central CORAL angiographic core laboratory readings; and to report outcomes after renal artery stent placement. During the roll-in phase, 239 patients (mean age, 70.2 y ± 9.0; 49% male) underwent renal artery stent procedures. Angiographic core laboratory analysis of renal arteriograms was done, and participants were followed at 1 month and 9 months. RESULTS: Major angiographic complications were identified in 28 (13%) subjects. Kidney function remained unchanged at the short (2-4 weeks) follow-up interval. Improvement in systolic blood pressure with use of distal embolic protection devices (n = 161) did not show any clinical benefit over nonuse of such devices (n = 78) in this small series. At 9 months, there were significantly more endpoints reported by site in subjects with bilateral renal artery stenosis (P = .01) and prior history of stroke (P = .03). CONCLUSIONS: In the roll-in phase of the CORAL study, a significant number of angiographic complications were identified. No effect was seen on estimated glomerular filtration rate after renal artery stent placement, but systolic blood pressure decreased significantly.

Stenting and medical therapy for atherosclerotic renal-artery stenosis.

BACKGROUND: Atherosclerotic renal-artery stenosis is a common problem in the elderly. Despite two randomized trials that did not show a benefit of renal-artery stenting with respect to kidney function, the usefulness of stenting for the prevention of major adverse renal and cardiovascular events is uncertain. METHODS: We randomly assigned 947 participants who had atherosclerotic renal-artery stenosis and either systolic hypertension while taking two or more antihypertensive drugs or chronic kidney disease to medical therapy plus renal-artery stenting or medical therapy alone. Participants were followed for the occurrence of adverse cardiovascular and renal events (a composite end point of death from cardiovascular or renal causes, myocardial infarction, stroke, hospitalization for congestive heart failure, progressive renal insufficiency, or the need for renal-replacement therapy). RESULTS: Over a median follow-up period of 43 months (interquartile range, 31 to 55), the rate of the primary composite end point did not differ significantly between participants who underwent stenting in addition to receiving medical therapy and those who received medical therapy alone (35.1% and 35.8%, respectively; hazard ratio with stenting, 0.94; 95% confidence interval [CI], 0.76 to 1.17; P=0.58). There were also no significant differences between the treatment groups in the rates of the individual components of the primary end point or in all-cause mortality. During follow-up, there was a consistent modest difference in systolic blood pressure favoring the stent group (-2.3 mm Hg; 95% CI, -4.4 to -0.2; P=0.03). CONCLUSIONS: Renal-artery stenting did not confer a significant benefit with respect to the prevention of clinical events when added to comprehensive, multifactorial medical therapy in people with atherosclerotic renal-artery stenosis and hypertension or chronic kidney disease. (Funded by the National Heart, Lung and Blood Institute and others; ClinicalTrials.gov number, NCT00081731.).

Clinical spectrum of SCN2A mutations expanding to Ohtahara syndrome.

OBJECTIVE: We aimed to investigate the possible association between SCN2A mutations and early-onset epileptic encephalopathies (EOEEs). METHODS: We recruited a total of 328 patients with EOEE, including 67 patients with Ohtahara syndrome (OS) and 150 with West syndrome. SCN2A mutations were examined using high resolution melt analysis or whole exome sequencing. RESULTS: We found 14 novel SCN2A missense mutations in 15 patients: 9 of 67 OS cases (13.4%), 1 of 150 West syndrome cases (0.67%), and 5 of 111 with unclassified EOEEs (4.5%). Twelve of the 14 mutations were confirmed as de novo, and all mutations were absent in 212 control exomes. A de novo mosaic mutation (c.3976G>C) with a mutant allele frequency of 18% was detected in one patient. One mutation (c.634A>G) was found in transcript variant 3, which is a neonatal isoform. All 9 mutations in patients with OS were located in linker regions between 2 transmembrane segments. In 7 of the 9 patients with OS, EEG findings transitioned from suppression-burst pattern to hypsarrhythmia. All 15 of the patients with novel SCN2A missense mutations had intractable seizures; 3 of them were seizure-free at the last medical examination. All patients showed severe developmental delay. CONCLUSIONS: Our study confirmed that SCN2A mutations are an important genetic cause of OS. Given the wide clinical spectrum associated with SCN2A mutations, genetic testing for SCN2A should be considered for children with different epileptic conditions.