Association of perceived work pace and physical work demands with occupational accidents: a cross-sectional study of ageing male construction workers in Denmark.

BACKGROUND: Occupational accidents continue to be a significant public health challenge worldwide. Construction workers in particular are at high risk of occupational accidents, and thus it is of major importance to identify possible predictors of occupational accidents among construction workers. We aimed to investigate the association between self-reported work pace and physical work demands and occupational accidents among ageing male construction workers in Denmark. METHODS: Data on perceived work pace, physical work demands, and occupational accidents was acquired from questionnaires sent to ageing construction workers in Denmark in 2016 as part of the ALFA project (ALdring og Fysisk Arbejde; Ageing and Physical Work). A sample of 1270 Danish male construction workers above 50 years of age was included in the present study. Multiple logistic regression models were applied, with adjustments for age, smoking, body mass index, musculoskeletal disorders, occupation, work experience, and support at work. RESULTS: Of 1270 construction workers, 166 (13.1%) reported an occupational accident within the last 12 months. There was no significant association between perceived work pace and occupational accidents, but physical work demands were associated with higher odds for occupational accidents, with an odds ratio of 2.27 (95% confidence interval 1.26-4.10) for medium physical work demands and 2.62 (95% confidence interval 1.50-4.57) for high physical work demands. CONCLUSIONS: Ageing male construction workers with high physical work demands had statistically significant higher odds of having an occupational accident. By contrast, perceived work pace was not associated with occupational accidents in this large cross-sectional study.

The association between perceived social support in adolescence and positive mental health outcomes in early adulthood: a prospective cohort study.

AIMS: The link between perceived social support and mental health has received much attention from numerous scientific fields in recent years. Most studies, however, have examined associations only over relatively short follow-up periods using global measures of perceived social support and dichotomous negative indicators of mental health. We investigated the long-term association between perceived social support from friends, parents and teachers and multiple positive hedonic and eudemonic indicators of mental health, including hope, meaningfulness and subjective well-being. METHODS: This study used questionnaire data from 2004, 2007 and 2010 from the West Jutland Birth Cohort study with linked register data. The study population consisted of 3681 adolescents born in 1989. Multiple linear and ordered logistic regression were used to analyse the association between perceived social support at age 14/15 years and mental health indicators at age 20/21 years while controlling for possible confounders, including the Big Five personality traits and baseline symptoms of depression. RESULTS: The results show that perceived social support from friends in adolescence was positively associated with all indicators of mental health in early adulthood. Furthermore, perceived paternal social support was positively associated with meaningfulness and subjective well-being, while perceived social support from teachers was positively associated with meaningfulness. CONCLUSIONS: Overall, the results from this study indicate that perceived social support in adolescence, particularly support from friends, could promote positive mental health outcomes in early adulthood.

The importance of adverse childhood experiences for labour market trajectories over the life course: a longitudinal study.

BACKGROUND: Transitioning from school to work is important in influencing people's trajectories throughout their life course. This study investigated the extent to which adverse childhood experiences (ACEs) were associated with differences in labour market trajectories for young adults in the context of a Nordic child care regime with low levels of child poverty. METHODS: Information on labour market participation, educational events, and public transfer records was recoded into seven state spaces for each month between ages 16 and 32 for a cohort of Danish adolescents born in a rural county in 1983 (N = 3373). Cluster analysis of the sequences using the optimal matching algorithm was used to identify groups with similar trajectories. Multinomial regression was used to assess the association between self-reported ACEs and cluster membership, taking gender and family of origin into account. RESULTS: 'In employment' was the state space in which the young adults spent the most time over their early life courses (mean: 85 out of 204 months; 42%). Cluster analysis identified three clusters. Cluster 3 was most distinct, where the mean time 'outside the labour market' was 149 months (73%), and only 17 months (8%) were spent 'in employment'. Cumulative ACEs increased the probability of being included in Cluster 3 (OR: 1.51). Experiencing parental divorce (OR: 3.05), witnessing a violent event (OR: 3.70), and being abused (OR: 5.64) were most strongly associated with Cluster 3 membership. CONCLUSIONS: Labour market trajectories among adolescents with a higher number of ACEs consisted of more time outside the labour market, compared to adolescents who had experienced fewer adversities. The lasting consequences of childhood adversity should be taken more into account in welfare policies, even in countries such as Denmark, with high social security levels and high-quality universal childcare.

The Effect of Colistin Treatment on the Selection of Colistin-Resistant Escherichia coli in Weaner Pigs.

The treatment of diarrhea in the postweaning period is a common reason for the use of antimicrobials in pig production, and Escherichia coli is the single most important causative agent for this condition. Colistin has recently been classified as a critically important antimicrobial for human health, as it is a last-resort drug against certain multi-drug-resistant Gram-negative bacteria. Therefore, the use of colistin has been significantly reduced in some countries, including Denmark. Despite this, the drug is still commonly used to treat diarrhea in pigs in many countries, and there is a need to understand the risks associated with this practice. We performed a prospective cohort study to investigate the effect of colistin treatment on the changes in the average minimum inhibitory concentration (MIC) in commensal E. coli in a pig herd where no colistin-resistant bacteria were detectable before treatment. One group of pigs was batch treated with colistin after the clinical observation of diarrhea, one group was batch treated with colistin approximately 10 days before the expected onset of diarrhea, and a control group was not treated with colistin but provided with nonantimicrobial antidiarrheal feed supplement. Treatment with colistin in the dose and time combinations used did not result in a significant increase in the average colistin MIC values in E. coli. Moreover, no E. coli strains showed a MIC above the breakpoint of >2 mg/L against colistin. Co-selection of resistance to other antimicrobials was not observed.

Coping strategies in adolescence and labour-market participation in young adulthood: A prospective birth cohort study.

Aims: The aim of this study was to investigate whether coping strategies in adolescence (14-15 years of age) were associated with labour-market participation (LMP) in young adulthood (25-26 years of age) and whether the association differed by sex. Methods: A birth cohort from the former county of Ringkjoebing, Denmark, consisting of 2826 individuals, comprised the study population. In 2004, the study population completed a questionnaire from which information about coping and covariates were gathered. Coping strategies were measured using five sub-scales of the Brief COPE Scale, which were combined into two overall coping strategies: active coping and avoidant coping. Ten years later, the participants were followed for a 52-week period in a register on social benefits. Logistic regression was applied to data, with adjustment for covariates: sex, parents' socio-economic status (education and income) and self-rated health. Results: A total of 2203 (78%) participants were categorised as high LMP at follow-up. No significant associations were found between active coping in adolescence and LMP in 2014/2015. For avoidant coping, in the fully adjusted model, medium-level avoidant coping was associated with higher odds (odds ratio (OR)=1.02 (95% confidence interval (CI) 0.83-1.25) of high LMP. For low avoidant coping, the OR was 1.37 (95% 1.07-1.75). For both coping strategies, sex did not modify the association. Conclusions: Findings showed that avoidant coping was significantly associated with high LMP. Further research is needed to investigate coping in relation to specific problem areas.

Haploinsufficiency of ARHGAP42 is associated with hypertension.

Family studies have established that the heritability of blood pressure is significant and genome-wide association studies (GWAS) have identified numerous susceptibility loci, including one within the non-coding part of Rho GTPase-activating protein 42 gene (ARHGAP42) on chromosome 11q22.1. Arhgap42-deficient mice have significantly elevated blood pressure, but the phenotypic effects of human variants in the coding part of the gene are unknown. In a Danish cohort of carriers with apparently balanced chromosomal rearrangements, we identified a family where a reciprocal translocation t(11;18)(q22.1;q12.2) segregated with hypertension and obesity. Clinical re-examination revealed that four carriers (age 50-77 years) have had hypertension for several years along with an increased body mass index (34-43 kg/m2). A younger carrier (age 23 years) had normal blood pressure and body mass index. Mapping of the chromosomal breakpoints with mate-pair and Sanger sequencing revealed truncation of ARHGAP42. A decreased expression level of ARHGAP42 mRNA in the blood was found in the translocation carriers relative to controls and allele-specific expression analysis showed monoallelic expression in the translocation carriers, confirming that the truncated allele of ARHGAP42 was not expressed. These findings support that haploinsufficiency of ARHGAP42 leads to an age-dependent hypertension. The other breakpoint truncated a regulatory domain of the CUGBP Elav-like family member 4 (CELF4) gene on chromosome 18q12.2 that harbours several GWAS signals for obesity. We thereby provide additional support for an obesity locus in the CELF4 domain.

Cohort profile: the Danish Future Occupation of Children and Adolescents cohort (the FOCA cohort): education, work-life, health and living conditions in a life-course perspective.

PURPOSE: The Future Occupation of Children and Adolescents cohort (the FOCA cohort) is a large population-based cohort study that was established as a resource for research in order to study adolescence factors and future educational and vocational trajectories in a life-course perspective. The cohort covers a broad array of themes within public health, including diseases and health behaviours. Through linkage to register data on the participants' parents, the cohort allows investigation of parental effects over time on adolescents' behaviours and interactions across generations. PARTICIPANTS: The FOCA cohort consists of 13 100 adolescents attending ninth grade in Denmark during the first quarter of 2017, independent of school type. FINDINGS TO DATE: Included were 6685 girls (51.03%) and 6415 boys (48.97%) with an average age of 15.85 years, representing 650 schools (37.23%), covering all options in the Danish school system and widely distributed across the country. The use of the personal identification number allowed for a merge of parents to all adolescents in the cohort, resulting in the identification of 25 911 registered parents. Register data on parents' socio-economic position and labour market history showed representativeness among the adolescents' socio-economic background compared with the general population in Denmark. FUTURE PLANS: The adolescents will be followed by ongoing linkage to administrative registers. Future studies will focus on factors affecting future health, education, work and well-being in a life-course perspective and for specific research projects, it will be possible to apply for permission to link data to further ongoing national registers covering all participants.

The effect of early-life and adult socioeconomic position on development of lifestyle-related diseases.

BACKGROUND: Early-life socioeconomic position (SEP) is associated with lifestyle-related diseases in adulthood. However, evidence is lacking on the extent to which adult SEP mediates this association. METHODS: Time to either chronic obstructive pulmonary disease (COPD), cardiovascular disease or diabetes were assessed in the Danish population born between 1961 and 1971 (n = 793 674) from age 30 until 2015. Early-life position was assessed in 1981 (by parental) and again at age 30 (own) by four markers; income, occupation, education-divided into high, middle, low-and a combined score for all markers. Using a counterfactual approach, we estimated the total effect of early-life position on disease onset and the degree to which adult position mediated this effect. RESULTS: Results of the time-to-event analysis showed a gradient of all early-life markers on the risk of developing all lifestyle-related diseases. Notably, comparing those in the lowest to the highest educational position, the hazard of COPD was 130% higher for women [hazard ratio = 2.30(95% confidence interval = 2.20-2.41)] and 114% higher for men [2.14 (2.05-2.25)]. About 67%(63-70%) of the effect of educational position was mediated through adult position for COPD, 55% for cardiovascular disease and 50% for diabetes. For the combined score 44, 29 and 33%, respectively, was mediated. CONCLUSION: About one-tenth to two-thirds of the effect of early-life position is mediated by the position attained in adulthood. The degree mediated depend on the outcome investigated, gender and the social position marker used indicating that alternative pathways may play a key role in developing effective policies targeting early-life behaviours.

Relative Age Effect and the Re-Selection of Danish Male Handball Players for National Teams.

The relationship between the date of birth and expertise in various sports among both elite and youth level athletes is well established, and known as the relative age effect (RAE). However, new results in for example Canadian Hockey and British cricket and rugby have indicated a reversal of RAE among selected talents where the youngest athletes are more likely to remain selected than their older peers. As such, RAE may therefore depend on the age and the level of competition. The purpose of this study was therefore to analyse RAE from the youth to senior national level in a sample of successful Danish male national teams. The sample included 244 players from Danish under-19, under-21 and senior national levels. These players have been part of successful teams, winning 18 medals at 24 youth European and World championships and 8 medals during 12 years at the senior level. The results showed a significant RAE on both youth and national levels. However, RAE was less marked from the under-19 to under-21 and further to the senior national level. Results show that at the national youth level talent selection favours the relatively older players, of whom a larger proportion fails to be re-selected to the senior level compared to their younger peers. RAE appears to play a central and reversing role in the identification and re-selection in Danish male handball. The results also show that the presence of both a constant and constituent year structure affects RAE, even when introduced at late adolescence.

Risks and Recommendations in Prenatally Detected De Novo Balanced Chromosomal Rearrangements from Assessment of Long-Term Outcomes.

The 6%-9% risk of an untoward outcome previously established by Warburton for prenatally detected de novo balanced chromosomal rearrangements (BCRs) does not account for long-term morbidity. We performed long-term follow-up (mean 17 years) of a registry-based nationwide cohort of 41 individuals carrying a prenatally detected de novo BCR with normal first trimester screening/ultrasound scan. We observed a significantly higher frequency of neurodevelopmental and/or neuropsychiatric disorders than in a matched control group (19.5% versus 8.3%, p = 0.04), which was increased to 26.8% upon clinical follow-up. Chromosomal microarray of 32 carriers revealed no pathogenic imbalances, illustrating a low prognostic value when fetal ultrasound scan is normal. In contrast, mate-pair sequencing revealed disrupted genes (ARID1B, NPAS3, CELF4), regulatory domains of known developmental genes (ZEB2, HOXC), and complex BCRs associated with adverse outcomes. Seven unmappable autosomal-autosomal BCRs with breakpoints involving pericentromeric/heterochromatic regions may represent a low-risk group. We performed independent phenotype-aware and blinded interpretation, which accurately predicted benign outcomes (specificity = 100%) but demonstrated relatively low sensitivity for prediction of the clinical outcome in affected carriers (sensitivity = 45%-55%). This sensitivity emphasizes the challenges associated with prenatal risk prediction for long-term morbidity in the absence of phenotypic data given the still immature annotation of the morbidity genome and poorly understood long-range regulatory mechanisms. In conclusion, we upwardly revise the previous estimates of Warburton to a morbidity risk of 27% and recommend sequencing of the chromosomal breakpoints as the first-tier diagnostic test in pregnancies with a de novo BCR.

Regulatory variants of FOXG1 in the context of its topological domain organisation.

FOXG1 syndrome is caused by FOXG1 intragenic point mutations, or by long-range position effects (LRPE) of intergenic structural variants. However, the size of the FOXG1 regulatory landscape is uncertain, because the associated topologically associating domain (TAD) in fibroblasts is split into two domains in embryonic stem cells (hESC). Indeed, it has been suggested that the pathogenetic mechanism of deletions that remove the stem-cell-specific TAD boundary may be enhancer adoption due to ectopic activity of enhancer(s) located in the distal hESC-TAD. Herein we map three de novo translocation breakpoints to the proximal regulatory domain of FOXG1. The classical FOXG1 syndrome in these and in other translocation patients, and in a patient with an intergenic deletion that removes the hESC-specific TAD boundary, do not support the hypothesised enhancer adoption as a main contributor to the FOXG1 syndrome. Also, virtual 4 C and HiC-interaction data suggest that the hESC-specific TAD boundary may not be critical for FOXG1 regulation in a majority of human cells and tissues, including brain tissues and a neuronal progenitor cell line. Our data support the importance of a critical regulatory region (SRO) proximal to the hESC-specific TAD boundary. We further narrow this critical region by a deletion distal to the hESC-specific boundary, associated with a milder clinical phenotype. The distance from FOXG1 to the SRO ( > 500 kb) highlight a limitation of ENCODE DNase hypersensitivity data for functional prediction of LRPE. Moreover, the SRO has little overlap with a cluster of frequently associating regions (FIREs) located in the proximal hESC-TAD.

The identification and functional annotation of RNA structures conserved in vertebrates.

Structured elements of RNA molecules are essential in, e.g., RNA stabilization, localization, and protein interaction, and their conservation across species suggests a common functional role. We computationally screened vertebrate genomes for conserved RNA structures (CRSs), leveraging structure-based, rather than sequence-based, alignments. After careful correction for sequence identity and GC content, we predict ∼516,000 human genomic regions containing CRSs. We find that a substantial fraction of human-mouse CRS regions (1) colocalize consistently with binding sites of the same RNA binding proteins (RBPs) or (2) are transcribed in corresponding tissues. Additionally, a CaptureSeq experiment revealed expression of many of our CRS regions in human fetal brain, including 662 novel ones. For selected human and mouse candidate pairs, qRT-PCR and in vitro RNA structure probing supported both shared expression and shared structure despite low abundance and low sequence identity. About 30,000 CRS regions are located near coding or long noncoding RNA genes or within enhancers. Structured (CRS overlapping) enhancer RNAs and extended 3' ends have significantly increased expression levels over their nonstructured counterparts. Our findings of transcribed uncharacterized regulatory regions that contain CRSs support their RNA-mediated functionality.

Bullied at school, bullied at work: a prospective study.

BACKGROUND: The consequences of childhood bullying victimisation are serious. Much previous research on risk factors for being bullied has used a cross-sectional design, impeding the possibility to draw conclusions on causality, and has not considered simultaneous effects of multiple risk factors. Paying closer attention to multiple risk factors for being bullying can provide a basis for designing intervention programmes to prevent or reduce bullying among children and adolescents. METHODS: Risk factors for bullying were examined by using questionnaire data collected in 2004 and 2007. In 2004, the participants were aged 14-15 years and 17-18 years in 2007. The baseline questionnaire was answered by 3054 individuals in 2004, and 2181 individuals participated in both rounds. We analysed risk factors for being bullied at the individual and societal level. Information on the social background of the participants was derived from a national register at Statistics Denmark. RESULTS: Several risk factors were identified. Being obese, low self-assessed position in school class, overprotective parents, low self-esteem, low sense of coherence and low socioeconomic status were risk factors for being bullied at school. Being overweight, smoking, low self-assessed position in class, low sense of coherence and low socioeconomic status were risk factors for being bullied at work. However, most associations between risk factors in 2004 and being bullied in 2007 disappeared after adjustment for being bullied in 2004. CONCLUSIONS: The strongest risk factor for being bullied was being previously bullied. Our results stress the importance of early prevention of bullying at schools. In addition, attention should be drawn to the role of overprotective parents.

Re-evaluation of groundwater monitoring data for glyphosate and bentazone by taking detection limits into account.

Current regulatory assessment of pesticide contamination of Danish groundwater is exclusively based on samples with pesticide concentrations above detection limit. Here we demonstrate that a realistic quantification of pesticide contamination requires the inclusion of "non-detect" samples i.e. samples with concentrations below the detection limit, as left-censored observations. The median calculated pesticide concentrations are shown to be reduced 10(4) to 10(5) fold for two representative herbicides (glyphosate and bentazone) relative to the median concentrations based upon observations above detection limits alone.

Acoustic Features for the Identification of Coronary Artery Disease.

GOAL: Earlier studies have documented that coronary artery disease (CAD) produces weak murmurs, which might be detected through analysis of heart sounds. An electronic stethoscope with a digital signal processing unit could be a low cost and easily applied method for diagnosis of CAD. The current study is a search for heart sound features which might identify CAD. METHODS: Nine different types of features from five overlapping frequency bands were obtained and analyzed using 435 recordings from 133 subjects. RESULTS: New features describing an increase in low-frequency power in CAD patients were identified. The features of the different types were relatively strongly correlated. Using a quadratic discriminant function, multiple features were combined into a CAD-score. The area under the receiving operating characteristic for the CAD score was 0.73 (95% CI: 0.69-0.78). CONCLUSION: The result confirms that there is a potential in heart sounds for the diagnosis of CAD, but that further improvements are necessary to gain clinical relevance.

Testing basic competency in knee arthroscopy using a virtual reality simulator: exploring validity and reliability.

BACKGROUND: Diagnostic knee arthroscopy is a common procedure that orthopaedic residents are expected to learn early in their training. Arthroscopy requires a different skill set from traditional open surgery, and many orthopaedic residents feel less prepared for arthroscopic procedures. Virtual reality simulation training and testing provide an opportunity to ensure basic competency before proceeding to supervised procedures in patients. METHODS: Twenty-six physicians (thirteen novices and thirteen experienced arthroscopic surgeons) were voluntarily recruited to perform a test consisting of five arthroscopic procedures on a knee arthroscopy simulator. Performance was evaluated by obtaining predefined metrics from the simulator for each procedure, and z-scores, describing suboptimal performance, were calculated from the metrics. The intercase reliability of the simulator metrics was explored by calculating an intraclass correlation coefficient. Finally, a pass-or-fail standard was set with use of the contrasting groups method, and the consequences of the pass-or-fail standard were explored. RESULTS: One procedure was excluded from the final test because of a lack of validity. The total Z-scores for the four procedures included in the final test showed an intercase reliability of 0.87 (95% confidence interval, 0.78 to 0.93). The total mean z-score (and standard deviation) was 38.6 ± 27.3 points for the novices and 0.0 ± 9.1 points for the experienced surgeons (p < 0.0005). The pass-or-fail standard was set at a total z-score of 15.5 points, resulting in two of the novices passing the test and a single experienced surgeon failing the test. CONCLUSIONS: By combining four procedures on a virtual reality arthroscopy simulator, it was possible to create a valid, reliable, and feasible test of basic arthroscopic competency and to establish a credible pass-or-fail standard. CLINICAL RELEVANCE: The simulation-based test and pass-or-fail standard could aid in assessing and ensuring basic competency of future orthopaedic residents before proceeding to supervised procedures in patients.

Individual social capital and survival: a population study with 5-year follow-up.

BACKGROUND: The concept of social capital has received increasing attention as a determinant of population survival, but its significance is uncertain. We examined the importance of social capital on survival in a population study while focusing on gender differences. METHODS: We used data from a Danish regional health survey with a five-year follow-up period, 2007-2012 (n = 9288, 53.5% men, 46.5% women). We investigated the association between social capital and all-cause mortality, performing separate analyses on a composite measure as well as four specific dimensions of social capital while controlling for covariates. Analyses were performed with Cox proportional hazard models by which hazard ratios and 95% confidence intervals were calculated. RESULTS: For women, higher levels of social capital were associated with lower all-cause mortality regardless of age, socioeconomic status, health, and health behaviour (HR = 0.586, 95% CI = 0.421-0.816) while no such association was found for men (HR = 0.949, 95% CI = 0.816-1.104). Analysing the specific dimensions of social capital, higher levels of trust and social network were significantly associated with lower all-cause mortality in women (HR = 0.827, 95% CI = 0.750-0.913 and HR = 0.832, 95% CI = 0.729-0.949, respectively). For men, strong social networks were associated with a higher risk of all-cause mortality (HR = 1.132, 95% CI = 1.017-1.260). Civic engagement had a similar effect for both men (HR = 0.848, 95% CI = 0.722-0.997) and women (HR = 0.848, 95% CI = 0.630-1.140). CONCLUSIONS: We found differential effects of social capital in men compared to women. The predictive effects on all-cause mortality of four specific dimensions of social capital varied. Gender stratified analysis and the use of multiple indicators to measure social capital are thus warranted in future research.

Neurodevelopmental disorders associated with dosage imbalance of ZBTB20 correlate with the morbidity spectrum of ZBTB20 candidate target genes.

BACKGROUND: Recently, a number of patients have been described with structural rearrangements at 3q13.31, delineating a novel microdeletion syndrome with common clinical features including developmental delay and other neurodevelopmental disorders (NDD). A smallest region of overlapping deletions (SRO) involved five RefSeq genes, including the transcription factor gene ZBTB20 and the dopamine receptor gene DRD3, considered as candidate genes for the syndrome. METHODS AND RESULTS: We used array comparative genomic hybridization and next-generation mate-pair sequencing to identify key structural rearrangements involving ZBTB20 in two patients with NDD. In a patient with developmental delay, attention-deficit hyperactivity disorder, psychosis, Tourette's syndrome and autistic traits, a de novo balanced t(3;18) translocation truncated ZBTB20. The other breakpoint did not disrupt any gene. In a second patient with developmental delay and autism, we detected the first microdeletion at 3q13.31, which truncated ZBTB20 but did not involve DRD3 or the other genes within the previously defined SRO. Zbtb20 directly represses 346 genes in the developing murine brain. Of the 342 human orthologous ZBTB20 candidate target genes, we found 68 associated with NDD. Using chromatin immunoprecipitation and quantitative PCR, we validated the in vivo binding of Zbtb20 in evolutionary conserved regions in six of these genes (Cntn4, Gad1, Nrxn1, Nrxn3, Scn2a, Snap25). CONCLUSIONS: Our study links dosage imbalance of ZBTB20 to a range of neurodevelopmental, cognitive and psychiatric disorders, likely mediated by dysregulation of multiple ZBTB20 target genes, and provides new knowledge on the genetic background of the NDD seen in the 3q13.31 microdeletion syndrome.

Epigenetic remodelling and dysregulation of DLGAP4 is linked with early-onset cerebellar ataxia.

Genome instability, epigenetic remodelling and structural chromosomal rearrangements are hallmarks of cancer. However, the coordinated epigenetic effects of constitutional chromosomal rearrangements that disrupt genes associated with congenital neurodevelopmental diseases are poorly understood. To understand the genetic-epigenetic interplay at breakpoints of chromosomal translocations disrupting CG-rich loci, we quantified epigenetic modifications at DLGAP4 (SAPAP4), a key post-synaptic density 95 (PSD95) associated gene, truncated by the chromosome translocation t(8;20)(p12;q11.23), co-segregating with cerebellar ataxia in a five-generation family. We report significant epigenetic remodelling of the DLGAP4 locus triggered by the t(8;20)(p12;q11.23) translocation and leading to dysregulation of DLGAP4 expression in affected carriers. Disruption of DLGAP4 results in monoallelic hypermethylation of the truncated DLGAP4 promoter CpG island. This induced hypermethylation is maintained in somatic cells of carriers across several generations in a t(8;20) dependent-manner however, is erased in the germ cells of the translocation carriers. Subsequently, chromatin remodelling of the locus-perturbed monoallelic expression of DLGAP4 mRNAs and non-coding RNAs in haploid cells having the translocation. Our results provide new mechanistic insight into the way a balanced chromosomal rearrangement associated with a neurodevelopmental disorder perturbs allele-specific epigenetic mechanisms at breakpoints leading to the deregulation of the truncated locus.

Influence of oxygen tension on dopaminergic differentiation of human fetal stem cells of midbrain and forebrain origin.

Neural stem cells (NSCs) constitute a promising source of cells for transplantation in Parkinson's disease (PD), but protocols for controlled dopaminergic differentiation are not yet available. Here we investigated the influence of oxygen on dopaminergic differentiation of human fetal NSCs derived from the midbrain and forebrain. Cells were differentiated for 10 days in vitro at low, physiological (3%) versus high, atmospheric (20%) oxygen tension. Low oxygen resulted in upregulation of vascular endothelial growth factor and increased the proportion of tyrosine hydroxylase-immunoreactive (TH-ir) cells in both types of cultures (midbrain: 9.1 ± 0.5 and 17.1 ± 0.4 (P<0.001); forebrain: 1.9 ± 0.4 and 3.9 ± 0.6 (P<0.01) percent of total cells). Regardless of oxygen levels, the content of TH-ir cells with mature neuronal morphologies was higher for midbrain as compared to forebrain cultures. Proliferative Ki67-ir cells were found in both types of cultures, but the relative proportion of these cells was significantly higher for forebrain NSCs cultured at low, as compared to high, oxygen tension. No such difference was detected for midbrain-derived cells. Western blot analysis revealed that low oxygen enhanced ß-tubulin III and GFAP expression in both cultures. Up-regulation of ß-tubulin III was most pronounced for midbrain cells, whereas GFAP expression was higher in forebrain as compared to midbrain cells. NSCs from both brain regions displayed less cell death when cultured at low oxygen tension. Following mictrotransplantation into mouse striatal slice cultures predifferentiated midbrain NSCs were found to proliferate and differentiate into substantial numbers of TH-ir neurons with mature neuronal morphologies, particularly at low oxygen. In contrast, predifferentiated forebrain NSCs microtransplanted using identical conditions displayed little proliferation and contained few TH-ir cells, all of which had an immature appearance. Our data may reflect differences in dopaminergic differentiation capacity and region-specific requirements of NSCs, with the dopamine-depleted striatum cultured at low oxygen offering an attractive micro-environment for midbrain NSCs.