Generation of two iPSC lines from adult central core disease patients with dominant missense variants in the RYR1 gene.

RYR1 variants are a common cause of congenital myopathies, including multi-minicore disease (MmD) and central core disease (CCD). Here, we generated iPSC lines from two CCD patients with dominant RYR1 missense variants that affect the transmembrane (pore) and SPRY3 protein domains (p.His4813Tyr and p.Asn1346Lys, respectively). Both lines had typical iPSC morphology, expressed canonical pluripotency markers, exhibited trilineage differentiation potential, and had normal karyotypes. Together with existing RYR1 iPSC lines, these represent important tools to study and develop treatments for RYR1-related myopathies.

Generation of two iPSC lines from patients with inherited central core disease and concurrent malignant hyperthermia caused by dominant missense variants in the RYR1 gene.

RYR1 variants are the most common genetic cause of congenital myopathies, and typically cause central core disease (CCD) and/or malignant hyperthermia (MH). Here, we generated iPSC lines from two patients with CCD and MH caused by dominant RYR1 variants within the central region of the protein (p.Val2168Met and p.Arg2508Cys). Both lines displayed typical iPSC morphology, uniform expression of pluripotency markers, trilineage differentiation potential, and had normal karyotypes. These are the first RYR1 iPSC lines from patients with both CCD and MH. As these are common CCD/MH variants, these lines should be useful to study these conditions and test therapeutics.

Generation of a human ACTA1-tdTomato reporter iPSC line using CRISPR/Cas9 editing.

We used gene editing to introduce DNA sequences encoding the tdTomato fluorescent protein into the α -skeletal actin 1 (ACTA1) locus to develop an ACTA1-tdTomato induced pluripotent stem cell reporter line for monitoring differentiation of skeletal muscle. This cell line will be used to better understand skeletal muscle maturation and development in vitro as well as provide a useful tool for drug screening and the evaluation of novel therapeutics for the treatment of skeletal muscle disease.

Generation of two induced pluripotent stem cell lines from a 33-year-old central core disease patient with a heterozygous dominant c.14145_14156delCTACTGGGACA (p.Asn4715_Asp4718del) deletion in the RYR1 gene.

Central core disease (CCD) is a congenital disorder that results in hypotonia, delayed motor development, and areas of reduced oxidative activity in the muscle fibre. Two induced pluripotent stem cell (iPSC) lines were generated from the lymphoblastoid cells of a 33-year-old male with CCD, caused by a previously unreported dominant c.14145_14156delCTACTGGGACA (p.Asn4715_Asp4718del) deletion in the RYR1 gene. Both lines demonstrated typical morphology, pluripotency, trilineage differentiation, and had a normal karyotype. As the first published iPSC model of CCD caused by an RYR1 variant these lines are a potential resource for further investigation of RYR1-related myopathies in a human context.

A KLHL40 3' UTR splice-altering variant causes milder NEM8, an under-appreciated disease mechanism.

Nemaline myopathy 8 (NEM8) is typically a severe autosomal recessive disorder associated with variants in the kelch-like family member 40 gene (KLHL40). Common features include fetal akinesia, fractures, contractures, dysphagia, respiratory failure and neonatal death. Here, we describe a 26-year-old man with relatively mild NEM8. He presented with hypotonia and bilateral femur fractures at birth, later developing bilateral Achilles' contractures, scoliosis, and elbow and knee contractures. He had walking difficulties throughout childhood and became wheelchair bound from age 13 after prolonged immobilization. Muscle magnetic resonance imaging at age 13 indicated prominent fat replacement in his pelvic girdle, posterior compartments of thighs and vastus intermedius. Muscle biopsy revealed nemaline bodies and intranuclear rods. RNA sequencing and western blotting of patient skeletal muscle indicated significant reduction in KLHL40 mRNA and protein, respectively. Using gene panel screening, exome sequencing and RNA sequencing, we identified compound heterozygous variants in KLHL40; a truncating 10.9 kb deletion in trans with a likely pathogenic variant (c.*152G > T) in the 3' untranslated region (UTR). Computational tools SpliceAI and Introme predicted the c.*152G > T variant created a cryptic donor splice site. RNA-seq and in vitro analyses indicated that the c.*152G > T variant induces multiple de novo splicing events that likely provoke nonsense mediated decay of KLHL40 mRNA explaining the loss of mRNA expression and protein abundance in the patient. Analysis of 3' UTR variants in ClinVar suggests variants that introduce aberrant 3' UTR splicing may be underrecognized in Mendelian disease. We encourage consideration of this mechanism during variant curation.

Integrated Forecasts Based on Public Health Surveillance and Meteorological Data Predict West Nile Virus in a High-Risk Region of North America.

BACKGROUND: West Nile virus (WNV), a global arbovirus, is the most prevalent mosquito-transmitted infection in the United States. Forecasts of WNV risk during the upcoming transmission season could provide the basis for targeted mosquito control and disease prevention efforts. We developed the Arbovirus Mapping and Prediction (ArboMAP) WNV forecasting system and used it in South Dakota from 2016 to 2019. This study reports a post hoc forecast validation and model comparison. OBJECTIVES: Our objective was to validate historical predictions of WNV cases with independent data that were not used for model calibration. We tested the hypothesis that predictive models based on mosquito surveillance data combined with meteorological variables were more accurate than models based on mosquito or meteorological data alone. METHODS: The ArboMAP system incorporated models that predicted the weekly probability of observing one or more human WNV cases in each county. We compared alternative models with different predictors including a) a baseline model based only on historical WNV cases, b) mosquito models based on seasonal patterns of infection rates, c) environmental models based on lagged meteorological variables, including temperature and vapor pressure deficit, d) combined models with mosquito infection rates and lagged meteorological variables, and e) ensembles of two or more combined models. During the WNV season, models were calibrated using data from previous years and weekly predictions were made using data from the current year. Forecasts were compared with observed cases to calculate the area under the receiver operating characteristic curve (AUC) and other metrics of spatial and temporal prediction error. RESULTS: Mosquito and environmental models outperformed the baseline model that included county-level averages and seasonal trends of WNV cases. Combined models were more accurate than models based only on meteorological or mosquito infection variables. The most accurate model was a simple ensemble mean of the two best combined models. Forecast accuracy increased rapidly from early June through early July and was stable thereafter, with a maximum AUC of 0.85. The model predictions captured the seasonal pattern of WNV as well as year-to-year variation in case numbers and the geographic pattern of cases. DISCUSSION: The predictions reached maximum accuracy early enough in the WNV season to allow public health responses before the peak of human cases in August. This early warning is necessary because other indicators of WNV risk, including early reports of human cases and mosquito abundance, are poor predictors of case numbers later in the season. https://doi.org/10.1289/EHP10287.

Generation of an induced pluripotent stem cell line from a 3-month-old nemaline myopathy patient with a heterozygous dominant c.515C > A (p.Ala172Glu) variant in the ACTA1 gene.

Variants in the ACTA1 gene are a common cause of nemaline myopathy (NM); a muscle disease that typically presents at birth or early childhood with hypotonia and muscle weakness. Here, we generated an induced pluripotent stem cell line (iPSC) from lymphoblastoid cells of a 3-month-old female patient with intermediate NM caused by a dominant ACTA1 variant (c.515C > A (p.Ala172Glu)). iPSCs showed typical morphology, expressed pluripotency markers, demonstrated trilineage differentiation potential, and had a normal karyotype. This line complements our previously published ACTA1 iPSC lines derived from patients with typical and severe NM.

Generation of two isogenic induced pluripotent stem cell lines from a 1-month-old nemaline myopathy patient harbouring a homozygous recessive c.121C > T (p.Arg39Ter) variant in the ACTA1 gene.

Nemaline myopathy (NM) is a congenital skeletal muscle disorder that typically results in muscle weakness and the presence of rod-like structures (nemaline bodies) in the sarcoplasma and/or in the nuclei of myofibres. Two induced pluripotent stem cell (iPSC) lines were generated from the lymphoblastoid cells of a 1-month-old male with severe NM caused by a homozygous recessive mutation in the ACTA1 gene (c.121C > T, p.Arg39Ter). The iPSC lines demonstrated typical morphology, expressed pluripotency markers, exhibited trilineage differentiation potential and displayed a normal karyotype. These isogenic lines represent a potential resource to investigate and model recessive ACTA1 disease in a human context.

Regulatory Architecture of the RCA Gene Cluster Captures an Intragenic TAD Boundary, CTCF-Mediated Chromatin Looping and a Long-Range Intergenic Enhancer.

The Regulators of Complement Activation (RCA) gene cluster comprises several tandemly arranged genes with shared functions within the immune system. RCA members, such as complement receptor 2 (CR2), are well-established susceptibility genes in complex autoimmune diseases. Altered expression of RCA genes has been demonstrated at both the functional and genetic level, but the mechanisms underlying their regulation are not fully characterised. We aimed to investigate the structural organisation of the RCA gene cluster to identify key regulatory elements that influence the expression of CR2 and other genes in this immunomodulatory region. Using 4C, we captured extensive CTCF-mediated chromatin looping across the RCA gene cluster in B cells and showed these were organised into two topologically associated domains (TADs). Interestingly, an inter-TAD boundary was located within the CR1 gene at a well-characterised segmental duplication. Additionally, we mapped numerous gene-gene and gene-enhancer interactions across the region, revealing extensive co-regulation. Importantly, we identified an intergenic enhancer and functionally demonstrated this element upregulates two RCA members (CR2 and CD55) in B cells. We have uncovered novel, long-range mechanisms whereby autoimmune disease susceptibility may be influenced by genetic variants, thus highlighting the important contribution of chromatin topology to gene regulation and complex genetic disease.

Bi-allelic MYH3 loss-of-function variants cause a lethal form of contractures, pterygia, and spondylocarpotarsal fusion syndrome 1B.

Arthrogryposis is a consequence of reduced fetal movements and arises due to environmental factors or underlying genetic defects, with extensive genetic heterogeneity. In many instances, the genes responsible are involved in neuromuscular function. Missense variants in the gene encoding embryonic myosin heavy chain (MYH3) usually cause distal arthrogryposis. Recently, mono-allelic or bi-allelic MYH3 variants have been associated with contractures, pterygia, and spondylocarpotarsal fusion syndrome 1 (CPSFS1A and CPSFS1B). Here we describe three fetuses presenting in the second trimester with a lethal form of arthrogryposis and pterygia and harbouring bi-allelic variants in MYH3. One proband was compound heterozygous for a missense change and an extended splice site variant, a second proband had a homozygous frameshift variant, and a third proband was homozygous for a nonsense variant. Minigene assays performed on the first fetus showed that the missense and extended splice site variants resulted in aberrant splicing, likely resulting in near complete loss of full-length MYH3 transcript. This study shows that loss of MYH3 is associated with a lethal arthrogryposis phenotype and highlights the utility of minigene assays to assess splicing.

Vaccine Breakthrough Cases in South Dakota: Impact of SARS-CoV-2 Variants in a Rural State.

BACKGROUND: Emergence of the SARS-CoV-2 Delta variant raised concern for greater transmissibility and severity of illness compared to the Alpha variant. Our objective was to compare SARS-CoV-2 vaccine breakthrough cases in South Dakota during the time periods where the Alpha and Delta variants of SARS-CoV-2 predominated. METHODS: Data were obtained from the South Dakota Department of Health's electronic disease surveillance system and South Dakota's Health Information Exchange. SARS-CoV-2 cases were matched with the immunization system data to verify vaccination status of vaccine breakthrough cases (VBC). The Alpha variant time-period (ATP) was defined as April 15-May 10, 2021 and the Delta variant time-period (DTP) as July 18-31, 2021. Case rates, demographics, risk factors, symptomology, and outcomes were compared for VBC during these periods. RESULTS: A total of 155 VBC were reported during the ATP and 153 during the DTP. The rate of SARS-CoV-2 VBC was 1.88 times higher for the DTP than the ATP. VBC during the ATP were more likely to present with no symptoms and during the DTP were more likely to present with subjective fever, cough, headache, loss or altered smell/taste, congestion, or postnasal drip. The average hospital length of stay was 6 days for the ATP and 4 days for the DTP. A total of 5 deaths were reported during the ATP compared to 1 death during the DTP. The non-statistically significant relation of the ATP and the DTP for hospital length of stay and number of deaths indicated a similar severity of disease. CONCLUSIONS: In fully vaccinated South Dakotans, the SARS-CoV-2 Delta variant was shown to cause 1.88 times higher breakthrough cases but resulted in similar severity of illness compared to the Alpha variant.

Improved CRISPR/Cas9 gene editing in primary human myoblasts using low confluency cultures on Matrigel.

BACKGROUND: CRISPR/Cas9 is an invaluable tool for studying cell biology and the development of molecular therapies. However, delivery of CRISPR/Cas9 components into some cell types remains a major hurdle. Primary human myoblasts are a valuable cell model for muscle studies, but are notoriously difficult to transfect. There are currently no commercial lipofection protocols tailored for primary myoblasts, and most generic guidelines simply recommend transfecting healthy cells at high confluency. This study aimed to maximize CRISPR/Cas9 transfection and editing in primary human myoblasts. METHODS: Since increased cell proliferation is associated with increased transfection efficiency, we investigated two factors known to influence myoblast proliferation: cell confluency, and a basement membrane matrix, Matrigel. CRISPR/Cas9 editing was performed by delivering Cas9 ribonucleoprotein complexes via lipofection into primary human myoblasts, cultured in wells with or without a Matrigel coating, at low (~ 40%) or high (~ 80%) confluency. RESULTS: Cells transfected at low confluency on Matrigel-coated wells had the highest levels of transfection, and were most effectively edited across three different target loci, achieving a maximum editing efficiency of 93.8%. On average, editing under these conditions was >4-fold higher compared to commercial recommendations (high confluency, uncoated wells). CONCLUSION: This study presents a simple, effective and economical method of maximizing CRISPR/Cas9-mediated gene editing in primary human myoblasts. This protocol could be a valuable tool for improving the genetic manipulation of cultured human skeletal muscle cells, and potentially be adapted for use in other cell types.

Generation of two isogenic induced pluripotent stem cell lines from a 10-year-old typical nemaline myopathy patient with a heterozygous dominant c.541G>A (p.Asp179Asn) pathogenic variant in the ACTA1 gene.

Nemaline myopathy (NM) is a congenital myopathy typically characterized by skeletal muscle weakness and the presence of nemaline bodies in myofibres. Approximately 25% of NM cases are caused by variants in ACTA1. We generated two induced pluripotent stem cell lines from lymphoblastoid cells of a 10-year-old female with typical NM harbouring a dominant pathogenic variant in ACTA1 (c.541C>A). The isogenic lines displayed typical iPSC morphology, expressed pluripotency markers, and could differentiate into each of the three germ layers. Although the lines have partial or complete X chromosome duplication, they may still prove useful as models of human ACTA1 disease.

Widespread Severe Acute Respiratory Syndrome Coronavirus 2 Transmission Among Attendees at a Large Motorcycle Rally and their Contacts, 30 US Jurisdictions, August-September, 2020.

The 2020 Sturgis motorcycle rally resulted in widespread transmission of severe acute respiratory syndrome coronavirus 2 across the United States. At least 649 coronavirus disease 2019 cases were identified, including secondary and tertiary spread to close contacts. To limit transmission, persons attending events should be vaccinated or wear masks and practice physical distancing if unvaccinated. Persons with a known exposure should be managed according to their coronavirus disease 2019 vaccination or prior infection status and may include quarantine and coronavirus disease 2019 testing.

Generation of two isogenic induced pluripotent stem cell lines from a 4-month-old severe nemaline myopathy patient with a heterozygous dominant c.553C > A (p.Arg183Ser) variant in the ACTA1 gene.

Nemaline myopathy (NM) is a congenital myopathy typically characterized by skeletal muscle weakness and the presence of abnormal thread- or rod-like structures (nemaline bodies) in myofibres. Pathogenic variants in the skeletal muscle alpha actin gene, ACTA1, cause approximately 25% of all NM cases. We generated two induced pluripotent stem cell lines from lymphoblastoid cells of a 4-month-old female with severe NM harbouring a dominant variant in ACTA1 (c.553C > A). The isogenic lines displayed characteristic iPSC morphology, expressed pluripotency markers, differentiated into cells of all three germ layers, and possessed normal karyotypes. These lines could be useful models of human ACTA1 disease.

Biallelic hypomorphic variants in ALDH1A2 cause a novel lethal human multiple congenital anomaly syndrome encompassing diaphragmatic, pulmonary, and cardiovascular defects.

This study shows a causal association between ALDH1A2 variants and a novel, severe multiple congenital anomaly syndrome in humans that is neonatally lethal due to associated pulmonary hypoplasia and respiratory failure. In two families, exome sequencing identified compound heterozygous missense variants in ALDH1A2. ALDH1A2 is involved in the conversion of retinol (vitamin A) into retinoic acid (RA), which is an essential regulator of diaphragm and cardiovascular formation during embryogenesis. Reduced RA causes cardiovascular, diaphragmatic, and associated pulmonary defects in several animal models, matching the phenotype observed in our patients. In silico protein modeling showed probable impairment of ALDH1A2 for three of the four substitutions. In vitro studies show a reduction of RA. Few pathogenic variants in genes encoding components of the retinoic signaling pathway have been described to date, likely due to embryonic lethality. Thus, this study contributes significantly to knowledge of the role of this pathway in human diaphragm and cardiovascular development and disease. Some clinical features in our patients are also observed in Fryns syndrome (MIM# 229850), syndromic microphthalmia 9 (MIM# 601186), and DiGeorge syndrome (MIM# 188400). Patients with similar clinical features who are genetically undiagnosed should be tested for recessive ALDH1A2-deficient malformation syndrome.

Motivation: how to create a cohort of engaged, energized, and happy radiology trainees.

Burnout among physicians continues to be a "hot topic" as medical culture struggles to adapt to the changing marketplace, where clinical demands are ever increasing but healthcare systems are pivoting to prefer value and cost-savings. To date, many attempts to understand and battle burnout center around the individual physician, rather than the system, limiting the medical community's ability to counter it successfully. The training environment is a common nidus for burnout. By promoting an understanding of motivation, happiness, and engagement in the workplace, we suggest several changes that training programs can make to minimize burnout and promote resident wellness. Creating a culture of support, promoting a positive work environment, building a cohesive team, and encouraging wellness both inside and outside the workplace stands to create engaged, happy, and motivated trainees who will hopefully continue to promote those strategies as they advance their careers.

Autosomal recessive cardiomyopathy and sudden cardiac death associated with variants in MYL3.

PURPOSE: Variants in genes encoding sarcomeric proteins are the most common cause of inherited cardiomyopathies. However, the underlying genetic cause remains unknown in many cases. We used exome sequencing to reveal the genetic etiology in patients with recessive familial cardiomyopathy. METHODS: Exome sequencing was carried out in three consanguineous families. Functional assessment of the variants was performed. RESULTS: Affected individuals presented with hypertrophic or dilated cardiomyopathy of variable severity from infantile- to early adulthood-onset and sudden cardiac death. We identified a homozygous missense substitution (c.170C>A, p.[Ala57Asp]), a homozygous translation stop codon variant (c.106G>T, p.[Glu36Ter]), and a presumable homozygous essential splice acceptor variant (c.482-1G>A, predicted to result in skipping of exon 5). Morpholino knockdown of the MYL3 orthologue in zebrafish, cmlc1, resulted in compromised cardiac function, which could not be rescued by reintroduction of MYL3 carrying either the nonsense c.106G>T or the missense c.170C>A variants. Minigene assay of the c.482-1G>A variant indicated a splicing defect likely resulting in disruption of the EF-hand Ca2+ binding domains. CONCLUSIONS: Our data demonstrate that homozygous MYL3 loss-of-function variants can cause of recessive cardiomyopathy and occurrence of sudden cardiac death, most likely due to impaired or loss of myosin essential light chain function.

Coronavirus Disease among Workers in Food Processing, Food Manufacturing, and Agriculture Workplaces.

We describe coronavirus disease (COVID-19) among US food manufacturing and agriculture workers and provide updated information on meat and poultry processing workers. Among 742 food and agriculture workplaces in 30 states, 8,978 workers had confirmed COVID-19; 55 workers died. Racial and ethnic minority workers could be disproportionately affected by COVID-19.

Neurogenetic fetal akinesia and arthrogryposis: genetics, expanding genotype-phenotypes and functional genomics.

BACKGROUND: Fetal akinesia and arthrogryposis are clinically and genetically heterogeneous and have traditionally been refractive to genetic diagnosis. The widespread availability of affordable genome-wide sequencing has facilitated accurate genetic diagnosis and gene discovery in these conditions. METHODS: We performed next generation sequencing (NGS) in 190 probands with a diagnosis of arthrogryposis multiplex congenita, distal arthrogryposis, fetal akinesia deformation sequence or multiple pterygium syndrome. This sequencing was a combination of bespoke neurogenetic disease gene panels and whole exome sequencing. Only class 4 and 5 variants were reported, except for two cases where the identified variants of unknown significance (VUS) are most likely to be causative for the observed phenotype. Co-segregation studies and confirmation of variants identified by NGS were performed where possible. Functional genomics was performed as required. RESULTS: Of the 190 probands, 81 received an accurate genetic diagnosis. All except two of these cases harboured class 4 and/or 5 variants based on the American College of Medical Genetics and Genomics guidelines. We identified phenotypic expansions associated with CACNA1S, CHRNB1, GMPPB and STAC3. We describe a total of 50 novel variants, including a novel missense variant in the recently identified gene for arthrogryposis with brain malformations-SMPD4. CONCLUSIONS: Comprehensive gene panels give a diagnosis for a substantial proportion (42%) of fetal akinesia and arthrogryposis cases, even in an unselected cohort. Recently identified genes account for a relatively large proportion, 32%, of the diagnoses. Diagnostic-research collaboration was critical to the diagnosis and variant interpretation in many cases, facilitated genotype-phenotype expansions and reclassified VUS through functional genomics.