Multiomic analyses implicate a neurodevelopmental program in the pathogenesis of cerebral arachnoid cysts

Systematic analysis of variants escaping nonsense-mediated decay uncovers candidate Mendelian diseases

Protein-truncating variants (PTVs) near the 3' end of genes may escape nonsense-mediated decay (NMD). PTVs in the NMD-escape region (PTVescs) can cause Mendelian disease but are difficult to interpret given their varying impact on protein function. Previously, PTVesc burden was assessed in an epilepsy cohort, but no large-scale analysis has systematically evaluated these variants in rare disease. We performed a retrospective analysis of 29,031 neurodevelopmental disorder (NDD) parent-offspring trios referred for clinical exome sequencing to identify PTVesc de novo mutations (DNMs). We identified 1,376 PTVesc DNMs and 133 genes that were significantly enriched (binomial p < 0.001). The PTVesc-enriched genes included those with PTVescs previously described to cause dominant Mendelian disease (e.g., SEMA6B, PPM1D, and DAGLA). We annotated ClinVar variants for PTVescs and identified 948 genes with at least one high-confidence pathogenic variant. Twenty-two known Mendelian PTVesc-enriched genes had no prior evidence of PTVesc-associated disease. We found 22 additional PTVesc-enriched genes that are not well established to be associated with Mendelian disease, several of which showed phenotypic similarity between individuals harboring PTVesc variants in the same gene. Four individuals with PTVesc mutations in RAB1A had similar phenotypes including NDD and spasticity. PTVesc mutations in IRF2BP1 were found in two individuals who each had severe immunodeficiency manifesting in NDD. Three individuals with PTVesc mutations in LDB1 all had NDD and multiple congenital anomalies. Using a large-scale, systematic analysis of DNMs, we extend the mutation spectrum for known Mendelian disease-associated genes and identify potentially novel disease-associated genes.

Human genetics and molecular genomics of Chiari malformation type 1

Chiari malformation type 1 (CM1) is the most common structural brain disorder involving the craniocervical junction, characterized by caudal displacement of the cerebellar tonsils below the foramen magnum into the spinal canal. Despite the heterogeneity of CM1, its poorly understood patho-etiology has led to a 'one-size-fits-all' surgical approach, with predictably high rates of morbidity and treatment failure. In this review we present multiplex CM1 families, associated Mendelian syndromes, and candidate genes from recent whole exome sequencing (WES) and other genetic studies that suggest a significant genetic contribution from inherited and de novo germline variants impacting transcription regulation, craniovertebral osteogenesis, and embryonic developmental signaling. We suggest that more extensive WES may identify clinically relevant, genetically defined CM1 subtypes distinguished by unique neuroradiographic and neurophysiological endophenotypes.

Co-morbid psychiatric disorders in children with arachnoid cyst

Arachnoid Cysts (AC) are benign lesions containing cerebrospinal fluid, and although most of them are asymptomatic, they can cause neurological symptoms like headaches, seizures, and neuropsychiatric problems. The aim of this study was to asses and document co-morbid psychiatric disorders in children with AC aged between 6 and 17. Wechsler Abbreviated Scale of Intelligence-Second Edition (WASI-II), a clinical measure used to assess the intelligence quotient (IQ) scores of the patients, Kiddie Schedule for Affective Disorders and Schizophrenia Present and Lifetime Version (K-SADS-PL; semi-structured interview) was used to assess psychiatric disorders among the patients. A total of 12 patients with AC was evaluated with an even distribution of males and females. Half of the patients had a normal IQ score with a mean IQ score of 104.5. Among patients with normal IQ scores, one patient had epilepsy and attention deficit hyperactivity disorder and two patients had epilepsy without any psychiatric disorder. The remaining six patients had moderate intellectual disability with a mean IQ of 48.2. Among them, three out of six had epilepsy and four had accompanying psychiatric disorders. It is therefore apparent that patients with AC have a high rate of co-morbid psychiatric disorders. Our study demonstrates that intellectual disability and psychiatric disorders should be evaluated in children with AC in the clinical settings.

An arachnoid cyst rupture complicated with subdural hygroma in a middle-aged woman: a case report and review of the literature

Background

Arachnoid cysts (ACs) account for about 1% of all intracranial mass lesions. The Sylvian fissure is the most common site of ACs which are usually asymptomatic. Traumatic rupture of arachnoid cysts complicated with subdural hygroma is a relatively rare entity in adults especially in females. There is no consensus on their management and each case could add to previous experiences leading to more uniform therapeutic measurements. This case encompasses a combination of watchful strategy, limited surgery and ultimately successful cyst fenestration which highlights a good outcome without complications by adopting a stepwise procedure.

Case presentation

Here, the case of a 51-year-old Persian woman being presented with a 2-month history of a localized headache which had begun 4 days after a minor head trauma. Early brain computed tomography (CT) obtained in another center at 4th day of post-injury which misinterpreted as an old infarct. Repeated CT in our center revealed a large AC of Sylvian fissure complicated with subdural hygroma. Initially a conservative management pursued but due to worsening of the symptoms, a burr-hole craniotomy performed for hygroma evacuation that subsequently followed by cyst fenestration about 1-month later.

Conclusion

Previous awareness about radiographic characteristics of ACs as well as employing appropriate imaging modality are necessary for correct and timely diagnosis of symptomatic patients after minor head trauma because incidentally found ACs might be the underpinning causes of symptoms. Also, following a multistage therapeutic process along with the involvement of patients in decision-making are of paramount importance.

Elovanoids are neural resiliency epigenomic regulators targeting histone modifications, DNA methylation, tau phosphorylation, telomere integrity, senescence programming, and dendrite integrity

Cellular identity, developmental reorganization, genomic structure modulation, and susceptibility to diseases are determined by epigenomic regulation by multiple signaling interplay. Here we demonstrate that elovanoids (ELVs), mediators derived from very-long-chain polyunsaturated fatty acids (VLC-PUFAs, n-3, C > 28), and their precursors in neurons in culture overcome the damage triggered by oligomeric amyloid-beta (OAβ), erastin (ferroptosis-dependent cell death), or other insults that target epigenomic signaling. We uncover that ELVs counteract damage targeting histones H3K9 and H3K27 methylation and acetylation; tau hyperphosphorylation (pThr181, pThr217, pThr231, and pSer202/pThr205 (AT8)); senescence gene programming (p16INK4a, p27KIP, p21CIP1, and p53); DNA methylation (DNAm) modifying enzymes: TET (DNA hydroxymethylase), DNA methyltransferase, DNA demethylase, and DNAm (5mC) phenotype. Moreover, ELVs revert OAβ-triggered telomere length (TL) attrition as well as upregulation of telomerase reverse transcriptase (TERT) expression fostering dendrite protection and neuronal survival. Thus, ELVs modulate epigenomic resiliency by pleiotropic interrelated signaling.