Modulating monocyte-derived macrophage polarization in cerebral ischemic injury with hyperglycemia.

Ischemic stroke (IS), characterized by high mortality rate, occurs owing to diminished or blocked blood flow to the brain. Hyperglycemia (HG) is a major contributor to the risk of IS. HG induces augmented oxidative stress and Blood-Brain Barrier breakdown, which increases the influx of blood-derived myeloid cells into the brain parenchyma. In cerebral ischemia, infiltrating monocytes undergo differentiation into pro-inflammatory or anti-inflammatory macrophages, having a large effect on outcomes of ischemic stroke. In addition, interleukin-4 (IL-4) and interleukin-13 (IL-13) engage in post-ischemia repair by polarizing the infiltrating monocytes into an anti-inflammatory phenotype. In this study, we aimed to determine the effect of phenotypic polarization of monocyte-derived macrophages on the prognosis of IS with HG (HG-IS). We first established a hyperglycemic mouse model using streptozotocin (150 mg/kg) and induced transient middle cerebral artery occlusion. We observed that blood-brain barrier permeability increased in HG-IS mice, as per two-photon live imaging and Evans blue staining. We also confirmed the increased infiltration of monocyte-derived macrophages and the downregulation of anti-inflammatory macrophages related to tissue remodeling after inflammation in HG-IS mice through immunohistochemistry, western blotting, and flow cytometry. We observed phenotypic changes in monocyte-derived macrophages, alleviated infarct volume, and improved motor function in HG-IS mice treated with IL-4 and IL-13. These findings suggest that the modulation of phenotypic changes in monocyte-derived macrophages following IS in hyperglycemic mice may influence ischemic recovery.

Control of OPC proliferation and repopulation by the intellectual disability gene PAK1 under homeostatic and demyelinating conditions.

Appropriate proliferation and repopulation of oligodendrocyte progenitor cells (OPCs) determine successful (re)myelination in homeostatic and demyelinating brains. Activating mutations in p21-activated kinase 1 (PAK1) cause intellectual disability, neurodevelopmental abnormality, and white matter anomaly in children. It remains unclear if and how PAK1 regulates oligodendroglial development. Here, we report that PAK1 controls proliferation and regeneration of OPCs. Unlike differentiating oligodendrocytes, OPCs display high PAK1 activity which maintains them in a proliferative state by modulating PDGFRa-mediated mitogenic signaling. PAK1-deficient or kinase-inhibited OPCs reduce their proliferation capacity and population expansion. Mice carrying OPC-specific PAK1 deletion or kinase inhibition are populated with fewer OPCs in the homeostatic and demyelinated CNS than control mice. Together, our findings suggest that kinase-activating PAK1 mutations stall OPCs in a progenitor state, impacting timely oligodendroglial differentiation in the CNS of affected children and that PAK1 is a potential molecular target for replenishing OPCs in demyelinating lesions.

Cost-effectiveness of mask mandates on subways to prevent SARS-CoV-2 transmission in the United States.

BACKGROUND: Community-based mask wearing has been shown to reduce the transmission of SARS-CoV-2. However, few studies have conducted an economic evaluation of mask mandates, specifically in public transportation settings. This study evaluated the cost-effectiveness of implementing mask mandates for subway passengers in the United States by evaluating its potential to reduce COVID-19 transmission during subway travel. MATERIALS AND METHODS: We assessed the health impacts and costs of subway mask mandates compared to mask recommendations based on the number of infections that would occur during subway travel in the U.S. Using a combined box and Wells-Riley infection model, we estimated monthly infections, hospitalizations, and deaths averted under a mask mandate scenario as compared to a mask recommendation scenario. The analysis included costs of implementing mask mandates and COVID-19 treatment from a limited societal perspective. The cost-effectiveness (net cost per averted death) of mandates was estimated for three different periods based on dominant SARS-CoV-2 variants: Alpha, Beta, and Gamma (November 2020 to February 2021); Delta (July to October 2021); and early Omicron (January to March 2022). RESULTS: Compared with mask recommendations only, mask mandates were cost-effective across all periods, with costs per averted death less than a threshold of $11.4 million (ranging from cost-saving to $3 million per averted death). Additionally, mask mandates were more cost-effective during the early Omicron period than the other two periods and were cost saving in January 2022. Our findings showed that mandates remained cost-effective when accounting for uncertainties in input parameters (e.g., even if mandates only resulted in small increases in mask usage by subway ridership). CONCLUSIONS: The findings highlight the economic value of mask mandates on subways, particularly during high virus transmissibility periods, during the COVID-19 pandemic. This study may inform stakeholders on mask mandate decisions during future outbreaks of novel viral respiratory diseases.

A GGC-repeat expansion in ZFHX3 encoding polyglycine causes spinocerebellar ataxia type 4 and impairs autophagy.

Despite linkage to chromosome 16q in 1996, the mutation causing spinocerebellar ataxia type 4 (SCA4), a late-onset sensory and cerebellar ataxia, remained unknown. Here, using long-read single-strand whole-genome sequencing (LR-GS), we identified a heterozygous GGC-repeat expansion in a large Utah pedigree encoding polyglycine (polyG) in zinc finger homeobox protein 3 (ZFHX3), also known as AT-binding transcription factor 1 (ATBF1). We queried 6,495 genome sequencing datasets and identified the repeat expansion in seven additional pedigrees. Ultrarare DNA variants near the repeat expansion indicate a common distant founder event in Sweden. Intranuclear ZFHX3-p62-ubiquitin aggregates were abundant in SCA4 basis pontis neurons. In fibroblasts and induced pluripotent stem cells, the GGC expansion led to increased ZFHX3 protein levels and abnormal autophagy, which were normalized with small interfering RNA-mediated ZFHX3 knockdown in both cell types. Improving autophagy points to a therapeutic avenue for this novel polyG disease. The coding GGC-repeat expansion in an extremely G+C-rich region was not detectable by short-read whole-exome sequencing, which demonstrates the power of LR-GS for variant discovery.

Regulation of CNS pathology by Serpina3n/SERPINA3: The knowns and the puzzles.

Neuroinflammation, blood-brain barrier (BBB) dysfunction, neuron and glia injury/death and myelin damage are common central nervous system (CNS) pathologies observed in various neurological diseases and injuries. Serine protease inhibitor (Serpin) clade A member 3n (Serpina3n), and its human orthologue SERPINA3, is an acute-phase inflammatory glycoprotein secreted primarily by the liver into the bloodstream in response to systemic inflammation. Clinically, SERPINA3 is dysregulated in brain cells, cerebrospinal fluid and plasma in various neurological conditions. Although it has been widely accepted that Serpina3n/SERPINA3 is a reliable biomarker of reactive astrocytes in diseased CNS, recent data have challenged this well-cited concept, suggesting instead that oligodendrocytes and neurons are the primary sources of Serpina3n/SERPINA3. The debate continues regarding whether Serpina3n/SERPINA3 induction represents a pathogenic or a protective mechanism. Here, we propose possible interpretations for previously controversial data and present perspectives regarding the potential role of Serpina3n/SERPINA3 in CNS pathologies, including demyelinating disorders where oligodendrocytes are the primary targets. We hypothesise that the 'good' or 'bad' aspects of Serpina3n/SERPINA3 depend on its cellular sources, its subcellular distribution (or mis-localisation) and/or disease/injury types. Furthermore, circulating Serpina3n/SERPINA3 may cross the BBB to impact CNS pathologies. Cell-specific genetic tools are critically important to tease out the potential roles of cell type-dependent Serpina3n in CNS diseases/injuries.

Association between Combustible Cigarettes and Noncombustible Nicotine or Tobacco Products and Generalized Anxiety Disorder Based on Data from the 8th Korea National Health and Nutrition Examination Survey 2021.

Background: Despite the increasing prevalence of anxiety disorders in Korea, there have been no nationwide studies on the association between tobacco status and generalized anxiety disorder (GAD). Furthermore, despite the increasing number of people using noncombustible nicotine or tobacco products (NNTPs), the association between NNTP use and GAD remains unclear. Therefore, this study investigated the association between tobacco use and GAD. Methods: This nationwide study used data from the 8th Korea National Health and Nutrition Examination Survey (2021) and included 5,454 adults aged ≥19 years who self-reported on the tobacco use and mental health sections. Multivariable logistic regression analysis was performed to investigate the odds ratios (ORs) of GAD (Generalized Anxiety Disorder-7 score ≥10) according to tobacco status among Korean adults. The severity of anxiety was assessed using the Generalized Anxiety Disorder-7 scale. Results: Compared to never tobacco users, the ORs of GAD for combustible cigarette smokers and NNTP users were 2.74 (95% confidence interval [CI], 1.66-4.50) and 2.11 (95% CI, 1.16-3.83), respectively. The OR of GAD for former tobacco users was 1.63 (95% CI, 0.98-2.72). Conclusion: Tobacco use (combustible cigarettes and NNTP) was positively associated with GAD. However, in former tobacco users, there was no significant association with GAD when compared with never tobacco users. Given the OR of GAD among tobacco users, it is crucial to pay attention to screening for GAD and implement appropriate early interventions.

Dispensable regulation of brain development and myelination by Serpina3n.

Serine protease inhibitor clade A member 3n (Serpina3n) or its human orthologue SERPINA3 is a secretory glycoprotein expressed primarily in the liver and brain under homeostatic conditions and dysregulated in various CNS pathologies. Yet its cellular expression profile and physiological significance in postnatal development remain elusive. Here, we showed that Serpina3n protein is expressed predominantly in oligodendroglial lineage cells in the postnatal CNS and that oligodendrocytes (OLs) responded to oxidative injury by upregulating Serpina3n production and secretion. Using loss-of-function genetic tools, we found that Serpina3n conditional knockout (cKO) from Olig2-expressing cells did not affect motor and cognitive functions in mice. Serpina3n depletion in Olig2-expressing cells did not appear to interfere with oligodendrocyte differentiation and developmental myelination nor affect the population of other glial cells and neurons in vivo. In vitro primary cell culture showed that Serpina3n-sufficient and -deficient oligodendroglial progenitor cells (OPCs) differentiated into myelin gene-expressing OLs comparatively. Together, these data suggest that Serpina3n plays a minor role, if any, in regulating brain neural cell development and myelination under homeostatic conditions and raise interests in pursuing its functional significance in CNS diseases and injuries.

Lessons Learned from Translating Genome Sequencing to Clinical Routine: Understanding the Accuracy of a Diagnostic Pipeline.

The potential of genome sequencing (GS), which allows detection of almost all types of genetic variation across nearly the entire genome of an individual, greatly expands the possibility for diagnosing genetic disorders. The opportunities provided with this single test are enticing to researchers and clinicians worldwide for human genetic research as well as clinical application. Multiple studies have highlighted the advantages of GS for genetic variant discovery, emphasizing its added value for routine clinical use. We have implemented GS as first-line genetic testing for patients with rare diseases. Here, we report on our experiences in establishing GS as a reliable diagnostic method for almost all types of genetic disorders, from validating diagnostic accuracy of sequencing pipelines to clinical implementation in routine practice.

Smoking Cessation and Pancreatic Cancer Risk in Individuals With Prediabetes and Diabetes: A Nationwide Cohort Study.

BACKGROUND: Individuals with diabetes and prediabetes are at increased risk of pancreatic cancer. However, little is known about the effects of smoking or smoking cessation on pancreatic cancer risk in individuals with diabetes and prediabetes. We investigated the association between smoking status (particularly smoking cessation) and pancreatic cancer risk according to glycemic status. PATIENTS AND METHODS: This nationwide cohort study included 9,520,629 adults without cancer who underwent the Korean National Health Screening in 2009 and were followed until 2018. Hazard ratios and 95% confidence intervals for pancreatic cancer were estimated after adjusting for potential confounders. RESULTS: During the 78.4 million person-years of follow-up, 15,245 patients were newly diagnosed with pancreatic cancer. Among individuals with diabetes and prediabetes, current smoking synergistically increased pancreatic cancer risk (all P<.01). However, quitters with diabetes and prediabetes had a pancreatic cancer risk comparable to that of never-smokers (all P>.05). For pancreatic cancer in current smokers, quitters, and never-smokers, respectively, the hazard ratios were 1.48 (95% CI, 1.40-1.58), 1.11 (95% CI, 1.03-1.19), and 1.00 (reference) among individuals with normoglycemia; 1.83 (95% CI, 1.70-1.97), 1.28 (95% CI, 1.18-1.39), and 1.20 (95% CI, 1.14-1.26) among individuals with prediabetes; and 2.72 (95% CI, 2.52-2.94), 1.78 (95% CI, 1.63-1.95), and 1.63 (95% CI, 1.54-1.72) among individuals with diabetes. There were no differences in risk between quitters with a <20 pack-year smoking history and never-smokers in all glycemic status groups. CONCLUSIONS: Pancreatic cancer risk synergistically increased in current smokers with diabetes and prediabetes. However, smoking cessation reduced the synergistically increased risk of pancreatic cancer to the level of never-smokers, especially when smoking history was <20 pack-years. More individualized and intensive cancer prevention education should be underscored for individuals at an increased risk of pancreatic cancer beyond the one-size-fits-all approach.

Association between Smoking Cessation and the Risk of Cholangiocarcinoma and Ampulla of Vater Cancer: A Nationwide Cohort Study.

Introduction: The association between smoking cessation and intrahepatic and extrahepatic cholangiocarcinoma (iCCA and eCCA) risk is unclear. Furthermore, the association in individuals with preexisting risk factors is unknown. We aimed to investigate the association between smoking status (especially smoking cessation) and CCA risk according to individuals' glycemic status. Methods: In this nationwide cohort study, 9,520,629 adults without cancer who underwent national health screening by the Korean National Health Insurance Service in 2009 were followed up through 2018. The hazard ratios (HRs) and 95% confidence intervals (CIs) for CCA were estimated after adjusting for potential confounders. Results: During the 78.3 person-years of follow-up, 16,236 individuals were newly diagnosed with CCA. Quitters had a significantly lower risk of iCCA and eCCA compared to current smokers in all glycemic status groups (all p < 0.01). The HRs (95% CIs) for iCCA in current smokers and quitters were 1.33 (1.24-1.43) versus 0.98 (0.90-1.06) in individuals with normoglycemia, 1.49 (1.37-1.63) versus 1.17 (1.06-1.28) in individuals with prediabetes, and 2.15 (1.96-2.37) versus 1.58 (1.42-1.75) in individuals with diabetes, compared to never-smokers with normoglycemia. Current smokers with diabetes or prediabetes had a synergistically increased risk of iCCA (all p < 0.01). However, quitters with diabetes and prediabetes had an iCCA risk comparable to that of never-smokers. Analysis of eCCA yielded similar results. Smoking was not independently associated with the risk of the ampulla of Vater cancer. However, smoking combined with diabetes or prediabetes was associated with an increased risk of the ampulla of Vater cancer (all p < 0.05). Conclusion: Smoking cessation was associated with a reduced risk of CCA, despite the synergistically increased risk in current smokers with diabetes and prediabetes. Our findings suggest a crucial opportunity to reduce the risk of CCA. More individualized and intensive cancer prevention education is needed against CCA.

Prevalence of diagnosed depression, anxiety, and ADHD among youth with type 1 or type 2 diabetes mellitus.

We examined the prevalence of diagnosed depression, anxiety, and ADHD among youth by diabetes type, insurance type, and race/ethnicity. These mental disorders were more prevalent among youth with diabetes, particularly those with type 2 diabetes, with non-Hispanic White youth with Medicaid and diabetes having a higher prevalence than other races/ethnicities.

HNRNPC haploinsufficiency affects alternative splicing of intellectual disability-associated genes and causes a neurodevelopmental disorder.

Heterogeneous nuclear ribonucleoprotein C (HNRNPC) is an essential, ubiquitously abundant protein involved in mRNA processing. Genetic variants in other members of the HNRNP family have been associated with neurodevelopmental disorders. Here, we describe 13 individuals with global developmental delay, intellectual disability, behavioral abnormalities, and subtle facial dysmorphology with heterozygous HNRNPC germline variants. Five of them bear an identical in-frame deletion of nine amino acids in the extreme C terminus. To study the effect of this recurrent variant as well as HNRNPC haploinsufficiency, we used induced pluripotent stem cells (iPSCs) and fibroblasts obtained from affected individuals. While protein localization and oligomerization were unaffected by the recurrent C-terminal deletion variant, total HNRNPC levels were decreased. Previously, reduced HNRNPC levels have been associated with changes in alternative splicing. Therefore, we performed a meta-analysis on published RNA-seq datasets of three different cell lines to identify a ubiquitous HNRNPC-dependent signature of alternative spliced exons. The identified signature was not only confirmed in fibroblasts obtained from an affected individual but also showed a significant enrichment for genes associated with intellectual disability. Hence, we assessed the effect of decreased and increased levels of HNRNPC on neuronal arborization and neuronal migration and found that either condition affects neuronal function. Taken together, our data indicate that HNRNPC haploinsufficiency affects alternative splicing of multiple intellectual disability-associated genes and that the developing brain is sensitive to aberrant levels of HNRNPC. Hence, our data strongly support the inclusion of HNRNPC to the family of HNRNP-related neurodevelopmental disorders.

Productivity costs associated with reactive school closures related to influenza or influenza-like illness in the United States from 2011 to 2019.

INTRODUCTION: Schools close in reaction to seasonal influenza outbreaks and, on occasion, pandemic influenza. The unintended costs of reactive school closures associated with influenza or influenza-like illness (ILI) has not been studied previously. We estimated the costs of ILI-related reactive school closures in the United States over eight academic years. METHODS: We used prospectively collected data on ILI-related reactive school closures from August 1, 2011 to June 30, 2019 to estimate the costs of the closures, which included productivity costs for parents, teachers, and non-teaching school staff. Productivity cost estimates were evaluated by multiplying the number of days for each closure by the state- and year-specific average hourly or daily wage rates for parents, teachers, and school staff. We subdivided total cost and cost per student estimates by school year, state, and urbanicity of school location. RESULTS: The estimated productivity cost of the closures was $476 million in total during the eight years, with most (90%) of the costs occurring between 2016-2017 and 2018-2019, and in Tennessee (55%) and Kentucky (21%). Among all U.S. public schools, the annual cost per student was much higher in Tennessee ($33) and Kentucky ($19) than any other state ($2.4 in the third highest state) or the national average ($1.2). The cost per student was higher in rural areas ($2.9) or towns ($2.5) than cities ($0.6) or suburbs ($0.5). Locations with higher costs tended to have both more closures and closures with longer durations. CONCLUSIONS: In recent years, we found significant heterogeneity in year-to-year costs of ILI-associated reactive school closures. These costs have been greatest in Tennessee and Kentucky and been elevated in rural or town areas relative to cities or suburbs. Our findings might provide evidence to support efforts to reduce the burden of seasonal influenza in these disproportionately impacted states or communities.

Increased Risk of Young-Onset Digestive Tract Cancers Among Young Adults Age 20-39 Years With Nonalcoholic Fatty Liver Disease: A Nationwide Cohort Study.

PURPOSE: Although the incidence of young-onset digestive tract cancers is increasing worldwide, their risk factors remain largely unknown. We investigated the association between nonalcoholic fatty liver disease (NAFLD) and young-onset digestive tract cancers. PATIENTS AND METHODS: This nationwide cohort study included 5,265,590 individuals age 20-39 years who underwent national health screening under the Korean National Health Insurance Service between 2009 and 2012. The fatty liver index was used as a diagnostic biomarker for NAFLD. The participants were followed up until December 2018 to determine the incidence of young-onset digestive tract cancers (ie, esophageal, stomach, colorectal, liver, pancreatic, biliary tract, and gallbladder). Multivariable Cox proportional hazards models were conducted to estimate the risk after adjusting for potential confounders. RESULTS: During the 38.8 million person-years of follow-up, 14,565 patients were newly diagnosed with young-onset digestive tract cancers. The cumulative incidence probability of each cancer type was consistently higher in individuals with NAFLD than in those without NAFLD (all log-rank P < .05). NAFLD was associated with an increased risk of overall digestive tract (adjusted hazard ratio [aHR], 1.16; 95% CI, 1.10 to 1.22), stomach (aHR, 1.14; 95% CI, 1.06 to 1.24), colorectal (aHR, 1.14; 95% CI, 1.06 to 1.22), liver (aHR, 1.13; 95% CI, 1.12 to 1.52), pancreatic (aHR, 1.23; 95% CI, 1.09 to 1.40), biliary tract (aHR, 1.29; 95% CI, 1.00 to 1.66), and gallbladder (aHR, 1.53; 95% CI, 1.01 to 2.31) cancer. These associations remained significant regardless of age, sex, smoking status, alcohol consumption, and obesity status (all P < .05; P for interaction >.05). The aHR for esophageal cancer was 1.67 (95% CI, 0.92 to 3.03). CONCLUSION: NAFLD may be an independent, modifiable risk factor for young-onset digestive tract cancers. Our findings suggest a crucial opportunity to reduce premature morbidity and mortality associated with young-onset digestive tract cancers in the next generation.

Threshold dose-response association between smoking pack-years and the risk of gallbladder cancer: A nationwide cohort study.

BACKGROUND AND AIMS: The association between smoking and gallbladder cancer (GBC) risk is unclear. We investigated the association between smoking (including pack-years) and GBC risk. We also examined the combined effects of smoking and diabetes or prediabetes on GBC risk. METHODS: This Korean nationwide cohort study included 9,520,629 adults without cancer who underwent national health screening in 2009 and were followed-up until 2018. Multivariable Cox proportional hazards models were used to determine risk estimates after adjusting for potential confounders. RESULTS: During 78.4 million person-years (mean 8.2 ± 0.9 years) of follow-up, we identified 6066 patients with newly diagnosed GBC. Current and former smokers were associated with increased GBC risk (hazard ratio [HR], 95% confidence interval [CI]: 1.117, 1.029-1.212 and 1.105, 1.016-1.202, respectively). Smoking of 20 to <30 and ≥30 pack-years was independently associated with increased GBC risk compared with never smoking (HR, 95% CI; 1.241, 1.100-1.400 and 1.231, 1.107-1.370, respectively). However, smoking of <10 and 10 to <20 pack-years was not. This threshold dose-response association between smoking pack-years and GBC risk was observed regardless of the glycaemic status (all P < 0.01). Furthermore, smoking of ≥20 pack-years and hyperglycaemia had a synergistic effect on the GBC risk (all P < 0.01). Smokers with ≥20 pack-years with diabetes had the highest risk of GBC compared to never smokers with normoglycaemia (HR, 1.658; 95% CI, 1.437-1.914). CONCLUSIONS: Smoking was associated with increased GBC risk with a threshold dose-response effect for smoking pack-years. The risk of GBC increases synergistically when smoking and hyperglycaemia coexist. More individualised cancer prevention education is required to reduce GBC risk.

Costs of malaria treatment in the United States.

We estimated inpatient and outpatient payments for malaria treatment in the USA. The mean cost per hospitalized patient was significantly higher than for non-hospitalized patients (e.g. $27 642 vs $1177 among patients with private insurance). Patients with severe malaria payed two to four times more than those hospitalized with uncomplicated malaria.

Association Between Glycemic Status and the Risk of Kidney Cancer in Men and Women: A Nationwide Cohort Study.

OBJECTIVE: Kidney cancer predominantly affects men, suggesting a biological protection against kidney cancer in women. We investigated the dose-response association between glycemic status and kidney cancer risk in men and women. RESEARCH DESIGN AND METHODS: In this nationwide cohort study, 9,492,331 adults without cancer who underwent national health screening in 2009 were followed up until 31 December 2018. We estimated kidney cancer risk using multivariable Cox proportional hazard regression models after adjusting for potential confounders. RESULTS: During the 78.1 million person-years of follow-up, incident kidney cancer occurred in 8,834 men and 3,547 women. The male-to-female ratio of the incidence rate was 2.1:1 in never-smokers with normoglycemia (17.8 vs. 8.5/100,000 person-years). Among never-smokers, men with diabetes, but not prediabetes, had an increased risk of kidney cancer (adjusted hazard ratio [aHR] 1.25 [95% CI 1.12-1.38] and 1.06 [0.97-1.15], respectively). Among never-smokers, women with both diabetes and prediabetes had an increased risk (aHR 1.34 [95% CI 1.21-1.49] and 1.19 [1.10-1.29], respectively) (Ptrend <0.01). Among smokers, men and women with diabetes had 49% and 85% increased kidney cancer risk (aHR 1.49 [95% CI 1.37-1.61] and 1.85 [1.26-2.73], respectively). CONCLUSIONS: Glycemic status and kidney cancer risk exhibited a dose-response association in women. Diabetes, but not prediabetes, was associated with an increased risk in men. Although women have a lower risk of kidney cancer than men, women with even prediabetes have an increased risk. These findings should not be overlooked when monitoring for kidney complications.

Bi-allelic loss-of-function variants in KIF21A cause severe fetal akinesia with arthrogryposis multiplex.

BACKGROUND: Fetal akinesia (FA) results in variable clinical presentations and has been associated with more than 166 different disease loci. However, the underlying molecular cause remains unclear in many individuals. We aimed to further define the set of genes involved. METHODS: We performed in-depth clinical characterisation and exome sequencing on a cohort of 23 FA index cases sharing arthrogryposis as a common feature. RESULTS: We identified likely pathogenic or pathogenic variants in 12 different established disease genes explaining the disease phenotype in 13 index cases and report 12 novel variants. In the unsolved families, a search for recessive-type variants affecting the same gene was performed; and in five affected fetuses of two unrelated families, a homozygous loss-of-function variant in the kinesin family member 21A gene (KIF21A) was found. CONCLUSION: Our study underlines the broad locus heterogeneity of FA with well-established and atypical genotype-phenotype associations. We describe KIF21A as a new factor implicated in the pathogenesis of severe neurogenic FA sequence with arthrogryposis of multiple joints, pulmonary hypoplasia and facial dysmorphisms. This hypothesis is further corroborated by a recent report on overlapping phenotypes observed in Kif21a null piglets.