Haploinsufficiency of ZFHX3, encoding a key player in neuronal development, causes syndromic intellectual disability.

Neurodevelopmental disorders (NDDs) result from impaired development and functioning of the brain. Here, we identify loss-of-function (LoF) variation in ZFHX3 as a cause for syndromic intellectual disability (ID). ZFHX3 is a zinc-finger homeodomain transcription factor involved in various biological processes, including cell differentiation and tumorigenesis. We describe 42 individuals with protein-truncating variants (PTVs) or (partial) deletions of ZFHX3, exhibiting variable intellectual disability and autism spectrum disorder, recurrent facial features, relative short stature, brachydactyly, and, rarely, cleft palate. ZFHX3 LoF associates with a specific methylation profile in whole blood extracted DNA. Nuclear abundance of ZFHX3 increases during human brain development and neuronal differentiation. ZFHX3 was found to interact with the chromatin remodeling BRG1/Brm-associated factor complex and the cleavage and polyadenylation complex, suggesting a function in chromatin remodeling and mRNA processing. Furthermore, ChIP-seq for ZFHX3 revealed that it predominantly binds promoters of genes involved in nervous system development. We conclude that loss-of-function variants in ZFHX3 are a cause of syndromic ID associating with a specific DNA methylation profile.

Gait alterations in patients with adult spinal deformity.

Background: Adult spinal deformity patients (ASD) experience altered spinal alignment affecting spatiotemporal parameters and joint kinematics. Differences in spinal deformity between patients with symptomatic idiopathic scoliosis (ID-ASD) and patients with "de novo" scoliosis (DN-ASD) may affect gait characteristics differently. This study aims to compare gait characteristics between ID-ASD, DN-ASD, and asymptomatic healthy matched controls. Methods: In this observational case-control study, ID-ASD (n = 24) and DN-ASD (n = 26) patients visiting the out-patient spine clinic and scheduled for long-segment spinal fusion were included. Patients were matched, based on age, gender, leg length and BMI, with asymptomatic healthy controls. Gait was measured at comfortable walking speed on an instrumented treadmill with 3D motion capture system. Trunk, pelvic and lower extremities range of motion (ROM) and spatiotemporal parameters (SPT) are presented as median (first and thirds quartile). Independent t-test or Mann-Whitney U test was used to compare ID-ASD, DN-ASD and controls. Statistical Parametric Mapping (independent t-test) was used to compare 3D joint kinematics. Results: DN-ASD patients walk with increased anterior trunk tilt during the whole gait cycle compared with ID-ASD patients and controls. ID-ASD walk with decreased trunk lateroflexion compared with DN-ASD and controls. DN-ASD showed decreased pelvic obliquity and -rotation, increased knee flexion, and decreased ankle plantar flexion. ID-ASD and DN-ASD displayed decreased trunk, pelvic and lower extremity ROM compared with controls, but increased pelvic tilt ROM. ID-ASD patients walked with comparable SPT to controls, whereas DN-ASD patients walked significantly slower with corresponding changes in SPT and wider steps. Conclusions: DN-ASD patients exhibit distinct alterations in SPT and kinematic gait characteristics compared with ID-ASD and controls. These alterations seem to be predominantly influenced by sagittal spinal malalignment and kinematic findings in ASD patients should not be generalized as such, but always be interpreted with consideration for the nature of the ASD.

A novel neurodevelopmental syndrome caused by loss-of-function of the Zinc Finger Homeobox 3 (ZFHX3) gene.

Neurodevelopmental disorders (NDDs) result from impaired development and functioning of the brain. Here, we identify loss-of-function variation in ZFHX3 as a novel cause for syndromic intellectual disability (ID). ZFHX3, previously known as ATBF1, is a zinc-finger homeodomain transcription factor involved in multiple biological processes including cell differentiation and tumorigenesis. Through international collaboration, we collected clinical and morphometric data (Face2Gene) of 41 individuals with protein truncating variants (PTVs) or (partial) deletions of ZFHX3 . We used data mining, RNA and protein analysis to identify the subcellular localization and spatiotemporal expression of ZFHX3 in multiple in vitro models. We identified the DNA targets of ZFHX3 using ChIP seq. Immunoprecipitation followed by mass spectrometry indicated potential binding partners of endogenous ZFHX3 in neural stem cells that were subsequently confirmed by reversed co-immunoprecipitation and western blot. We evaluated a DNA methylation profile associated with ZFHX3 haploinsufficiency using DNA methylation analysis on whole blood extracted DNA of six individuals with ZFHX3 PTVs and four with a (partial) deletion of ZFHX3 . A reversed genetic approach characterized the ZFHX3 orthologue in Drosophila melanogaster . Loss-of-function variation of ZFHX3 consistently associates with (mild) ID and/or behavioural problems, postnatal growth retardation, feeding difficulties, and recognizable facial characteristics, including the rare occurrence of cleft palate. Nuclear abundance of ZFHX3 increases during human brain development and neuronal differentiation in neural stem cells and SH-SY5Y cells, ZFHX3 interacts with the chromatin remodelling BRG1/Brm-associated factor complex and the cleavage and polyadenylation complex. In line with a role for chromatin remodelling, ZFHX3 haploinsufficiency associates with a specific DNA methylation profile in leukocyte-derived DNA. The target genes of ZFHX3 are implicated in neuron and axon development. In Drosophila melanogaster , z fh2, considered to be the ZFHX3 orthologue, is expressed in the third instar larval brain. Ubiquitous and neuron-specific knockdown of zfh2 results in adult lethality underscoring a key role for zfh2 in development and neurodevelopment. Interestingly, ectopic expression of zfh2 as well as ZFHX3 in the developing wing disc results in a thoracic cleft phenotype. Collectively, our data shows that loss-of-function variants in ZFHX3 are a cause of syndromic ID, that associates with a specific DNA methylation profile. Furthermore, we show that ZFHX3 participates in chromatin remodelling and mRNA processing.

Effectiveness and cost-effectiveness of dynamic bracing versus standard care alone in patients suffering from osteoporotic vertebral compression fractures: protocol for a multicentre, two-armed, parallel-group randomised controlled trial with 12 months of follow-up.

INTRODUCTION: Patients with osteoporosis may suffer from a fracture after minimal trauma. Osteoporotic vertebral compression fractures (OVCFs) are among the most common fractures, often leading to substantial pain. There is a need for evidence-based conservative treatment to aid in the management of OVCFs. The objective of this randomised controlled trial (RCT) is to evaluate the effectiveness and cost-effectiveness of dynamic bracing in addition to standard care for improving quality of life (QoL) in patients suffering from an OVCF. METHODS AND ANALYSIS: Ninety-eight postmenopausal women from two academic and four community hospitals with a recent symptomatic thoracolumbar OVCF will be randomised into either the standard care or dynamic bracing group. In the dynamic bracing group, the Spinova Osteo orthosis will be used in addition to standard care. Standard care comprises pain control with analgesics, physical therapy and osteoporosis medication. The primary outcome parameter is QoL 1 year after inclusion, as measured by the Quality of Life Questionnaire of the European Foundation for Osteoporosis (QUALEFFO-41). Secondary outcome parameters are pain, pain medication used, functional disability, sagittal spinal alignment, recurrence rate of OVCFs and physical activity in daily life. A trial-based economic evaluation consisting of both cost-effectiveness analysis and cost-utility analysis will be performed based on empirical data obtained in the RCT. A process evaluation will assess the feasibility of dynamic bracing. All outcomes will be assessed at baseline, 6 weeks, 3 months, 6 months, 9 months and 12 months. ETHICS AND DISSEMINATION: Ethical approval has been granted by the Medical Ethics Committee, University Hospital Maastricht and Maastricht University (METC azM/UM) (NL74552.068.20/METC 20-055). Patients will be included only after verification of eligibility and obtaining written informed consent. Results will be disseminated via the Dutch National Osteoporosis Patient Society and via publications and conferences. TRIAL REGISTRATION NUMBER: NL8746.

Luminescent Human iPSC-Derived Neurospheroids Enable Modeling of Neurotoxicity After Oxygen-glucose Deprivation.

Despite the considerable impact of stroke on both the individual and on society, a neuroprotective therapy for stroke patients is missing. This is partially due to the current lack of a physiologically relevant human in vitro stroke model. To address this problem, we have developed a luminescent human iPSC-derived neurospheroid model that enables real-time read-out of neural viability after ischemia-like conditions. We subjected 1- and 4-week-old neurospheroids, generated from iPSC-derived neural stem cells, to 6 h of oxygen-glucose deprivation (OGD) and measured neurospheroid luminescence. For both, we detected a decrease in luminescent signal due to ensuing neurotoxicity, as confirmed by conventional LDH assay and flow cytometric viability analysis. Remarkably, 1-week-old, but not 4-week-old neurospheroids recovered from OGD-induced injury, as evidenced by their reduced but overall increasing luminescence over time. This underscores the need for more mature neurospheroids, more faithfully recapitulating the in vivo situation. Furthermore, treatment of oxygen- and glucose-deprived neurospheroids with the pan-caspase inhibitor Z-VAD-FMK did not increase overall neural survival, despite its successful attenuation of apoptosis, in a human-based 3D environment. Nevertheless, owing to its three-dimensional organization and real-time viability reporting potential, the luminescent neurospheroids may become readily adopted in high-throughput screens aimed at identification of new therapeutic agents to treat acute ischemic stroke patients.

Biomechanical Evaluation of Semi-rigid Junctional Fixation Using a Novel Cable Anchor System to Prevent Proximal Junctional Failure in Adult Spinal Deformity Surgery.

STUDY DESIGN: A porcine cadaveric biomechanical study. OBJECTIVE: To biomechanically evaluate a novel Cable Anchor System as semi-rigid junctional fixation technique for the prevention of proximal junctional failure after adult spinal deformity surgery and to make a comparison to alternative promising prophylactic techniques. SUMMARY OF BACKGROUND DATA: The abrupt change of stiffness at the proximal end of a pedicle screw construct is a major risk factor for the development of proximal junctional failure after adult spinal deformity surgery. A number of techniques that aim to provide a gradual transition zone in range of motion (ROM) at the proximal junction have previously been studied. In this study, the design of a novel Cable Anchor System, which comprises a polyethylene cable for rod fixation, is assessed. METHODS: Ten T6-T13 porcine spine segments were subjected to cyclic 4 Nm pure-moment loading. The following conditions were tested: uninstrumented, 3 level pedicle screw fixation (PSF), and PSF with supplementary Cable Anchors applied proximally at 1-level (Anchor1) or 2-levels (Anchor2), transverse process hooks (TPH), and 2-level sublaminar tapes (Tape2). The normalized segmental range of motion in the junctional zone was compared using one-way analysis of variance and linear regression. RESULTS: Statistical comparison at the level proximal to PSF showed significantly lower ROMs for all techniques compared to PSF fixation alone in all movement directions. Linear regression demonstrated a higher linearity for Anchor1 (0.820) and Anchor2 (0.923) in the junctional zone in comparison to PSF (1-level: 0.529 and 2-level: 0.421). This linearity was similar to the compared techniques (TPH and Tape2). CONCLUSION: The Cable Anchor System presented in this study demonstrated a gradual ROM transition zone at the proximal end of a rigid pedicle screw construct similar to TPH and 2-level sublaminar tape semi-rigid junctional fixation constructs, while providing the benefit of preserving the posterior ligament complex.Level of Evidence: 5.

Recurrent chromosomal imbalances provide selective advantage to human embryonic stem cells under enhanced replicative stress conditions.

Human embryonic stem cells (hESCs) and embryonal tumors share a number of common features, including a compromised G1/S checkpoint. Consequently, these rapidly dividing hESCs and cancer cells undergo elevated levels of replicative stress, inducing genomic instability that drives chromosomal imbalances. In this context, it is of interest that long-term in vitro cultured hESCs exhibit a remarkable high incidence of segmental DNA copy number gains, some of which are also highly recurrent in certain malignancies such as 17q gain (17q+). The selective advantage of DNA copy number changes in these cells has been attributed to several underlying processes including enhanced proliferation. We hypothesized that these recurrent chromosomal imbalances become rapidly embedded in the cultured hESCs through a replicative stress driven Darwinian selection process. To this end, we compared the effect of hydroxyurea-induced replicative stress vs normal growth conditions in an equally mixed cell population of isogenic euploid and 17q + hESCs. We could show that 17q + hESCs rapidly overtook normal hESCs. Our data suggest that recurrent chromosomal segmental gains provide a proliferative advantage to hESCs under increased replicative stress, a process that may also explain the highly recurrent nature of certain imbalances in cancer.

Expanding the molecular spectrum and the neurological phenotype related to CAMTA1 variants.

The CAMTA1-associated phenotype was initially defined in patients with intragenic deletions and duplications who showed nonprogressive congenital ataxia, with or without intellectual disability. Here, we describe 10 individuals with CAMTA1 variants: nine previously unreported (likely) pathogenic variants comprising one missense, four frameshift and four nonsense variants, and one missense variant of unknown significance. Six patients were diagnosed following whole exome sequencing and four individuals with exome-based targeted panel analysis. Most of them present with developmental delay, manifesting in speech and motor delay. Other frequent findings are hypotonia, cognitive impairment, cerebellar dysfunction, oculomotor abnormalities, and behavioral problems. Feeding problems occur more frequently than previously observed. In addition, we present a systematic review of 19 previously published individuals with causal variants, including copy number, truncating, and missense variants. We note a tendency of more severe cognitive impairment and recurrent dysmorphic features in individuals with a copy number variant. Pathogenic variants are predominantly observed in and near the N- and C- terminal functional domains. Clinical heterogeneity is observed, but 3'-terminal variants seem to associate with less pronounced cerebellar dysfunction.

Gait in patients with symptomatic osteoporotic vertebral compression fractures over 6 months of recovery.

BACKGROUND: One factor related to disability in people with spinal deformity is decreased postural control and increased risk of falling. However, little is known about the effect of osteoporotic vertebral compression fractures (OVCFs) and their recovery on gait and stability. Walking characteristics of older adults with and without vertebral fractures have not yet been compared. AIMS: The purpose of the current study was to examine the spatiotemporal gait parameters and their variability in patients with an OVCF and healthy participants during treadmill walking at baseline and after 6 months of recovery. METHODS: Twelve female patients suffering a symptomatic OVCF were compared to 11 matched controls. Gait analysis was performed with a dual-belt instrumented treadmill with a 180° projection screen providing a virtual environment (computer-assisted rehabilitation environment). Results of patients with an OVCF and healthy participants were compared. Furthermore, spatiotemporal gait parameters were assessed over 6 months following the fracture. RESULTS: Patients suffering from an OVCF appeared to walk with significantly shorter, faster and wider strides compared to their healthy counterparts. Although stride time and length improved over time, the majority of the parameters analysed remained unchanged after 6 months of conservative treatment. DISCUSSION: Since patients do not fully recover to their previous level of mobility after 6 months of conservative treatment for OVCF, it appears of high clinical importance to add balance and gait training to the treatment algorithm of OVCFs. CONCLUSIONS: Patients suffering from an OVCF walk with shorter, faster and wider strides compared to their healthy counterparts adopt a less stable body configuration in the anterior direction, potentially increasing their risk of forward falls if perturbed. Although stride time and stride length improve over time even reaching healthy levels again, patients significantly deviate from normal gait patterns (e.g. in stability and step width) after 6 months of conservative treatment.

Internet usage of women attempting pregnancy and pregnant women in the Netherlands.

OBJECTIVES: Research focused on Internet behavior by women attempting pregnancy and pregnant women is scarce. Some research has been done in other countries, however it cannot be assumed those results also apply to Dutch women. STUDY DESIGN: A descriptive cross-sectional study was performed using an Internet-questionnaire among women attempting pregnancy and pregnant women. MAIN OUTCOME MEASURES: The aim of this study was to identify the Internet behavior of women attempting pregnancy and pregnant women in the Netherlands. RESULTS: In total, 365 women completed the questionnaire. Of these, 95.6% used the Internet as an information source before or during their pregnancy. Most searched topics were fetal development, lifestyle and pregnancy as well as birth complications. Over 90% of the women thought the information found was reliable and based pregnancy related decisions on this information. However, only 50.1% of the women discussed the information found with their caregiver. Of the respondents, 76.2% thought a reliable website is needed provided by the caregivers. CONCLUSIONS: A vast majority of Dutch women attempting pregnancy and Dutch pregnant women use the Internet to search for information and to make decisions about their pregnancy, however they were not satisfied with the information available online. A reliable, informative, interactive and up-to-date website is deemed necessary.

Effect of a semirigid thoracolumbar orthosis on gait and sagittal alignment in patients with an osteoporotic vertebral compression fracture.

BACKGROUND: An important goal in the treatment of osteoporotic vertebral compression fractures (OVCFs) is the prevention of new vertebral fractures and the subsequent progression to global sagittal malalignment. Current conservative treatment is multimodal and comprises analgesics, medication for osteoporosis, and physical therapy. However, little is known about the value of orthoses in the treatment of OVCFs. AIMS: The primary purpose of this study was to examine the direct effect of a semirigid thoracolumbar orthosis on gait in patients suffering from an OVCF. The secondary purpose was to evaluate changes in gait, radiographic sagittal alignment, pain, and quality of life over time. METHODS: Fifteen postmenopausal patients with an OVCF were treated with a semirigid thoracolumbar orthosis. At baseline, after 6 weeks, and after 6 months, gait analysis was performed with a dual belt-instrumented treadmill with a 180° projection screen providing a virtual environment (computer-assisted rehabilitation environment) combined with clinical and radiographic assessments. RESULTS: At baseline, bracing caused a significantly more upright posture during walking and patients walked faster, with larger strides, longer stride times, and lower cadence compared to walking without orthosis. After 6 weeks, radiographic and dynamic sagittal alignment had improved compared to baseline. The observed effect was gone after 6 months, when the orthosis was not worn anymore. CONCLUSION: A semirigid thoracolumbar orthosis seems to have a positive effect on gait and stability in patients suffering from an OVCF, as was shown by a more upright posture, which may result in decreased compressive loading of the vertebrae. For studying the true effectiveness of dynamic bracing in the treatment of OVCFs, a prospective, randomized controlled trial will be needed.

Implementation of patient-reported outcome measures in appropriateness criteria of surgery for degenerative lumbar scoliosis.

BACKGROUND CONTEXT: Degenerative lumbar scoliosis (DLS) is an increasingly common spinal disorder of which current management is characterized by a substantial variety in treatment advice. To improve evidence-based clinical decision-making and increase uniformity and transparency of care, the Scoliosis Research Society established appropriateness criteria for surgery for DLS. In these criteria, however, the patient perspective was not formally incorporated. Since patient perspective is an increasingly important consideration in informed decision-making, embedding patient-reported outcome measures (PROMs) in the appropriateness criteria would allow for an objective and transparent patient-centered approach. PURPOSE: To evaluate the extent that patient perspective is integrated into the appropriateness criteria of surgery for DLS. STUDY DESIGN: Single center, retrospective, cohort study. PATIENT SAMPLE: 150 patients with symptomatic degenerative lumbar scoliosis. OUTCOME MEASURES: The association between appropriateness for surgery and various PROMs [Visual Analogue Scale for pain, Short Form 36 (SF-36), Pain Catastrophizing Scale (PCS), Hospital Anxiety Depression Scale (HADS), and Oswestry Disability Index (ODI)]. METHODS: Medical records of all patients with symptomatic DLS were reviewed and scored according to the appropriateness criteria. To assess the association between the appropriateness criteria and the validated PROMs, analysis of variance was used to test for differences in PROMS for each of the three categories resulting from the appropriateness criteria. To assess how well PROMs can discriminate between appropriate and inappropriate, we used a logistic regression analysis. Discriminative ability was subsequently determined by computing the area under the curve (AUC), resulting from the logistic regression analysis. Spearman rank analysis was used to establish a correlation pattern between the PROMs used and the appropriateness criteria. RESULTS: There was a significant association between the appropriateness of surgery and the PROMs. The discriminative ability for appropriateness of surgery for PROMs as a group was strong (AUC of 0.83). However, when considered in isolation, the predictive power of any individual PROMs was poor. The different categories of the appropriateness criteria significantly coincided with the PROMs used. CONCLUSION: There is a statistically significant association between the appropriateness criteria of surgery for DLS and PROMs. Implementation of PROMs into the appropriateness criteria may lead to more transparent, quantifiable and uniform clinical decision making for DLS.

Prediction of mechanical complications in adult spinal deformity surgery-the GAP score versus the Schwab classification.

BACKGROUND CONTEXT: Surgery for adult spinal deformity is a challenging and complex procedure with high reported complication (8.4%-42%) and revision rates (9%-17.6%). Failure to achieve or maintain adequate postoperative sagittal alignment has been reported to be the main cause of mechanical complications. In order to define appropriate surgical targets, the Scoliosis Research Society-Schwab classification and the Global Alignment and Proportion (GAP) score were established. In the literature, no study has yet compared these classification systems with respect to the risk of developing mechanical complications. PURPOSE: To assess and compare the ability of the Schwab classification and the GAP score to predict mechanical complications following adult spinal deformity surgery. STUDY DESIGN: Two-center, retrospective cohort study. PATIENT SAMPLE: Thirty-nine patients suffering adult spinal deformity who underwent long segment spinal fusion (≥4 levels), minimum follow-up of 2years. OUTCOME MEASURES: The ability of the Schwab classification and GAP score to predict mechanical failure was determined by computing the Area Under the receiver operating characteristic curve. METHODS: Full-spine pre- and postoperative radiographs of all patients were analyzed for mechanical complications. Subsequently, the pre- and postoperative Schwab and GAP score were determined. Logistic regression analysis was used to assess the ability of both systems to determine which was the most appropriate for the prediction of mechanical failure. Correlations between the various factors constituting the GAP score and Schwab classification were estimated using the Spearman rank order correlation coefficient. RESULTS: The results demonstrated that both classification systems are capable of predicting radiographic evidence of mechanical failure; however, the GAP score proved to be significantly better (p=.003). The relative pelvic version of the GAP score serves a similar role as the pelvic tilt modifier from the Schwab classification (ρ=-0.84, p<.01). The relative lumbar lordosis from the GAP score functions much like the PI-LL modifier from the Schwab classification (ρ=-0.94, p<.01). The GAP score is most significantly dependent on relative spinopelvic alignment, relative lumbar lordosis, and relative pelvic version (ρ=0.85, ρ=0.84, and ρ=0.84, respectively, p<.01). Correlation with the lordosis distribution index was also significant but was not as strong (ρ=0.65, p<.01). Age, on the contrary, showed poor correlation with the GAP score (ρ=0.17, p=.300). CONCLUSIONS: Both the Schwab classification and the GAP score are capable of predicting mechanical complications. The GAP score proved to be significantly more appropriate. This difference is probably attributed to the fact that in the GAP score all parameters are related to the patient's individual pelvic incidence.

CRISPR/Cas9-mediated genome editing in naïve human embryonic stem cells.

The combination of genome-edited human embryonic stem cells (hESCs) and subsequent neural differentiation is a powerful tool to study neurodevelopmental disorders. Since the naïve state of pluripotency has favourable characteristics for efficient genome-editing, we optimized a workflow for the CRISPR/Cas9 system in these naïve stem cells. Editing efficiencies of respectively 1.3-8.4% and 3.8-19% were generated with the Cas9 nuclease and the D10A Cas9 nickase mutant. Next to this, wildtype and genome-edited naïve hESCs were successfully differentiated to neural progenitor cells. As a proof-of-principle of our workflow, two monoclonal genome-edited naïve hESCs colonies were obtained for TUNA, a long non-coding RNA involved in pluripotency and neural differentiation. In these genome-edited hESCs, an effect was seen on expression of TUNA, although not on neural differentiation potential. In conclusion, we optimized a genome-editing workflow in naïve hESCs that can be used to study candidate genes involved in neural differentiation and/or functioning.

Reduction of intradiscal pressure by the use of polycarbonate-urethane rods as compared to titanium rods in posterior thoracolumbar spinal fixation.

Loss of sagittal alignment and balance in adult spinal deformity can cause severe pain, disability and progressive neurological deficit. When conservative treatment has failed, spinal fusion using rigid instrumentation is currently the salvage treatment to stop further curve progression. However, fusion surgery is associated with high revision rates due to instrumentation failure and proximal junctional failure, especially if patients also suffer from osteoporosis. To address these drawbacks, a less rigid rod construct is proposed, which is hypothesized to provide a more gradual transition of force and load distribution over spinal segments in comparison to stiff titanium rods. In this study, the effect of variation in rod stiffness on the intradiscal pressure (IDP) of fixed spinal segments during flexion-compression loading was assessed. An ex vivo multisegment (porcine) flexion-compression spine test comparing rigid titanium rods with more flexible polycarbonate-urethane (PCU) rods was used. An increase in peak IDP was found for both the titanium and PCU instrumentation groups as compared to the uninstrumented controls. The peak IDP for the spines instrumented with the PCU rods was significantly lower in comparison to the titanium instrumentation group. These results demonstrated the differences in mechanical load transfer characteristics between PCU and titanium rod constructs when subjected to flexion-compression loading. The concept of stabilization with a less rigid rod may be an alternative to fusion with rigid instrumentation, with the aim of decreasing mechanical stress on the instrumented segments and the possible benefit of a decrease in the incidence of screw pullout.

Identification of long non-coding RNAs involved in neuronal development and intellectual disability.

Recently, exome sequencing led to the identification of causal mutations in 16-31% of patients with intellectual disability (ID), leaving the underlying cause for many patients unidentified. In this context, the noncoding part of the human genome remains largely unexplored. For many long non-coding RNAs (lncRNAs) a crucial role in neurodevelopment and hence the human brain is anticipated. Here we aimed at identifying lncRNAs associated with neuronal development and ID. Therefore, we applied an integrated genomics approach, harnessing several public epigenetic datasets. We found that the presence of neuron-specific H3K4me3 confers the highest specificity for genes involved in neurodevelopment and ID. Based on the presence of this feature and GWAS hits for CNS disorders, we identified 53 candidate lncRNA genes. Extensive expression profiling on human brain samples and other tissues, followed by Gene Set Enrichment Analysis indicates that at least 24 of these lncRNAs are indeed implicated in processes such as synaptic transmission, nervous system development and neurogenesis. The bidirectional or antisense overlapping orientation relative to multiple coding genes involved in neuronal processes supports these results. In conclusion, we identified several lncRNA genes putatively involved in neurodevelopment and CNS disorders, providing a resource for functional studies.

Synthesis and characterization of a new vertebroplasty cement based on gold-containing PMMA microspheres.

There are a number of drawbacks to incorporating large concentrations of barium sulfate (BaSO4) as the radiopacifier in PMMA-based bone cements for percutaneous vertebroplasty. These include adverse effects on injectability, viscosity profile, setting time, mechanical properties of the cement and bone resorption. We have synthesized a novel cement that is designed to address some of these drawbacks. Its powder includes PMMA microspheres in which gold particles are embedded and its monomer is the same as that used in commercial cements for vertebroplasty. In comparison to one such commercial cement brand, VertaPlex™, the new cement has longer doughing time, longer injection time, higher compressive strength, higher compressive modulus, and is superior in terms of cytotoxicity. For augmentation of fractured fresh-frozen cadaveric vertebral bodies (T6-L5) using simulated vertebroplasty, results for compressive strength and compressive stiffness of the construct and the percentage of the volume of the vertebral body filled by the cement were comparable for the two cements although the radiopacity of the new cement was significantly lower than that for VertaPlex™. The present results indicate that the new cement warrants further study.

Refinement of the critical 2p25.3 deletion region: the role of MYT1L in intellectual disability and obesity.

PURPOSE: Submicroscopic deletions of chromosome band 2p25.3 are associated with intellectual disability and/or central obesity. Although MYT1L is believed to be a critical gene responsible for intellectual disability, so far no unequivocal data have confirmed this hypothesis. METHODS: In this study we evaluated a cohort of 22 patients (15 sporadic patients and two families) with a 2p25.3 aberration to further refine the clinical phenotype and to delineate the role of MYT1L in intellectual disability and obesity. In addition, myt1l spatiotemporal expression in zebrafish embryos was analyzed by quantitative polymerase chain reaction and whole-mount in situ hybridization. RESULTS: Complete MYT1L deletion, intragenic deletion, or duplication was observed in all sporadic patients, in addition to two patients with a de novo point mutation in MYT1L. The familial cases comprise a 6-Mb deletion in a father and his three children and a 5' MYT1L overlapping duplication in a father and his two children. Expression analysis in zebrafish embryos shows specific myt1l expression in the developing brain. CONCLUSION: Our data strongly strengthen the hypothesis that MYT1L is the causal gene for the observed syndromal intellectual disability. Moreover, because 17 patients present with obesity/overweight, haploinsufficiency of MYT1L might predispose to weight problems with childhood onset.Genet Med 17 6, 460-466.