Neurologic phenotypes associated with COL4A1/2 mutations: Expanding the spectrum of disease

Stroke Genetics: Discovery, Insight Into Mechanisms, and Clinical Perspectives

Stroke is the second leading cause of death worldwide and a complex, heterogeneous condition. In this review, we provide an overview of the current knowledge on monogenic and multifactorial forms of stroke, highlighting recent insight into the continuum between these. We describe how, in recent years, large-scale genome-wide association studies have enabled major progress in deciphering the genetic basis for stroke and its subtypes, although more research is needed to interpret these findings. We cover the potential of stroke genetics to reveal novel pathophysiological processes underlying stroke, to accelerate the discovery of new therapeutic approaches, and to identify individuals in the population who are at high risk of stroke and could be targeted for tailored preventative interventions.

Ischemic Stroke Genetics: What Is New and How to Apply It in Clinical Practice?

The etiology of ischemic stroke is multifactorial. Although receiving less emphasis, genetic causes make a significant contribution to ischemic stroke genesis, especially in early-onset stroke. Several stroke classification systems based on genetic information corresponding to various stroke phenotypes were proposed. Twin and family history studies, as well as candidate gene approach, are common methods to discover genetic causes of stroke, however, both have their own limitations. Genome-wide association studies and next generation sequencing are more efficient, promising and increasingly used for daily diagnostics. Some monogenic disorders, despite covering only about 7% of stroke etiology, may cause well-known clinical manifestations that include stroke. Polygenic disorders are more frequent, causing about 38% of all ischemic strokes, and their identification is a rapidly developing field of modern stroke genetics. Current advances in human genetics provide opportunity for personalized prevention of stroke and novel treatment possibilities. Genetic risk scores (GRS) and extended polygenic risk scores (PRS) estimate cumulative contribution of known genetic factors to a specific outcome of stroke. Combining those scores with clinical information and risk factor profiles might result in better primary stroke prevention. Some authors encourage the use of stroke gene panels for stroke risk evaluation and further stroke research. Moreover, new biomarkers for stroke genetic causes and novel targets for gene therapy are on the horizon. In this article, we summarize the latest evidence and perspectives of ischemic stroke genetics that could be of interest to the practitioner and useful for day-to-day clinical work.

Epilepsy and related challenges in children with COL4A1 and COL4A2 mutations: A Gould syndrome patient registry

Recently, patient advocacy groups started using the name Gould syndrome to describe clinical features of COL4A1 and COL4A2 mutations. Gould syndrome is increasingly identified in genetic screening panels, and because it is a rare disease, there is a disproportionate burden on families to understand the disease and chart the course for clinical care. Among the chief concerns for caregivers of children with Gould syndrome are the challenges faced because of epilepsy, including severe manifestations such as infantile spasms. To document the concerns of the patient population, the Gould Syndrome Foundation established the Gould Syndrome Global Registry (GSGR).

METHODS

The Gould Syndrome Foundation developed questions for the GSGR with iterative input from patients and caregivers. An institutional review board issued an exemption determination before data collection began. Participants were recruited through social media and clinician referrals. All participants consented electronically, and the data were collected and managed using REDCap electronic data capture tools. De-identified data representing responses received between October 2019 and February 2021 were exported and analyzed with IBM SPSS 27 using descriptive statistics (mean, standard deviation, frequency, range, and percent).

RESULTS

Seventy families from twelve countries provided data for the registry, representing 100 affected people (40 adults and 60 children). This analysis represents a subanalysis of the 35 out of 60 children <=18 years of age who reported a history of seizures. Nearly half of these participants were diagnosed with infantile spasms. Participants with epilepsy frequently reported developmental delays (88.6%), stroke (60.0%), cerebral palsy (65.7%), and constipation (57.1%). Ten (28.6%) children use a feeding tube. Despite the fact that more than half of respondents reported stroke, only 34.3% reported ever receiving education on stroke recognition.

CONCLUSION

Here we describe the development and deployment of the first global registry for individuals and family members with Gould syndrome, caused by mutations in COL4A1 and COL4A2. It is important for pediatric neurologists to have access to resources to provide families upon diagnosis. Specifically, all families with Gould Syndrome must have access to infantile spasms awareness and stroke education materials. The Gould Syndrome Foundation is planning several improvements to this patient registry which will encourage collaboration and innovation for the benefit of people living with Gould syndrome.

Genetic causes underlying grey matter heterotopia

Grey matter heterotopia (GMH) can cause of seizures and are associated with a wide range of neurodevelopmental disorders and syndromes. They are caused by a failure of neuronal migration during fetal development, leading to clusters of neurons that have not reached their final destination in the cerebral cortex. We have performed an extensive literature search in Pubmed, OMIM, and Google scholar and provide an overview of known genetic associations with periventricular nodular heterotopia (PNVH), subcortical band heterotopia (SBH) and other subcortical heterotopia (SUBH). We classified the heterotopias as PVNH, SBH, SUBH or other and collected the genetic information, frequency, imaging features and salient features in tables for every subtype of heterotopia. This resulted in 105 PVNH, 16 SBH and 25 SUBH gene/locus associations, making a total of 146 genes and chromosomal loci. Our study emphasizes the extreme genetic heterogeneity underlying GMH. It will aid the clinician in establishing an differential diagnosis and eventually a molecular diagnosis in GMH patients. A diagnosis enables proper counseling of prognosis and recurrence risks, and enables individualized patient management.

Progressive cerebral atrophies in three children with COL4A1 mutations

BACKGROUND

The collagen type IV alpha 1 chain (COL4A1) gene on 13q34 encodes one chain of collagen. COL4A1 mutations have been identified as the cause of a group of multisystemic conditions in humans, including the brain, eyes, kidneys, muscles, and other organs at any age. Brain imaging shows a wide spectrum of abnormalities, including porencephaly, schizencephaly, polymicrogyria focal cortical dysplasia, periventricular leukoencephalopathy, ventricular dysmorphisms, and multiple brain calcifications. However, there are no reports in the literature showing progressive radiological findings in consecutive follow-up scans. Herein, we report three cases of COL4A1 mutations with porencephaly from gestation to five years of age or longer, and describe their clinical and brain imaging findings.

CASE REPORTS

We retrospectively reviewed the clinical symptoms and radiological findings, including brain magnetic resonance imaging (MRI) and computed tomography (CT), in three female patients with COL4A1 mutations. Their mutations were c.4843G>A (p.Glu1615Lys), c.1835G>A (p.Gly612Asp), and c.3556+1G>T respectively. All the three cases represented porencephaly in the fetal period; severe hemolytic anemia in the neonatal period; and drug-resistant epilepsy, global developmental delay, and spastic quadriplegia in their childhood.

RESULTS

Brain MRI and CT showed progressive white matter atrophy from gestation to five-year follow-up or later. Minor cerebral hemorrhage without symptoms occasionally occurred in one patient. Despite brain changes, the clinical picture was stable during early childhood.

CONCLUSIONS

COL4A1 mutations may cause progressive cerebral atrophy beyond early childhood.

Predicting functional circular RNA-based competitive endogenous RNA network in gastric carcinoma using novel bioinformatics analysis

Gastric cancer (GC) remains one of the most prevalent types of malignancies worldwide, and also one of the most reported lethal tumor-related diseases. Circular RNAs (circRNAs) have been certified to be trapped in multiple aspects of GC pathogenesis. Yet, the mechanism of this regulation is mostly undefined. This research is designed to discover the vital circRNA-microRNA (miRNA)-messenger RNA (mRNA) regulatory network in GC. Expression profiles with diverse levels including circRNAs, miRNAs, and mRNAs were all determined using microarray public datasets from Gene Expression Ominous (GEO). The differential circRNAs expressions were recognized against the published robust rank aggregation algorithm. Besides, a circRNA-based competitive endogenous RNA (ceRNA) interaction network was visualized via Cytoscape software (version 3.8.0). Functional and pathway enrichment analysis associated with differentially expressed targeted mRNAs were conducted using Cytoscape and an online bioinformatics database. Furthermore, an interconnected protein-protein interaction association network which consisted of 51 mRNAs was predicted, and hub genes were screened using STRING and CytoHubba. Then, several hub genes were chosen to explore their expression associated with survival rate and clinical stage in GEPIA and Kaplan-Meier Plotter databases. Finally, a carefully designed circRNA-related ceRNA regulatory subnetwork including four circRNAs, six miRNAs, and eight key hub genes was structured using the online bioinformatics tool.

Neonatal encephalopathy: Etiologies other than hypoxic-ischemic encephalopathy

Neonatal encephalopathy (NE) describes the clinical syndrome of a newborn with abnormal brain function that may result from a variety of etiologies. HIE should be distinguished from neonatal encephalopathy due to other causes using data gathered from the history, physical and neurological exam, and further investigations. Identifying the underlying cause of encephalopathy has important treatment implications. This review outlines conditions that cause NE and may be mistaken for HIE, along with their distinguishing clinical features, pathophysiology, investigations, and treatments. NE due to brain malformations, vascular causes, neuromuscular causes, genetic conditions, neurogenetic disorders and inborn errors of metabolism, central nervous system (CNS) and systemic infections, and toxic/metabolic disturbances are discussed.

A Novel Mutation in COL4A1 Gene in a Chinese Family with Pontine Autosomal Dominant Microangiopathy and Leukoencephalopathy

Pontine autosomal dominant microangiopathy and leukoencephalopathy (PADMAL) is a rare hereditary cerebral small vessel disease. We report a novel collagen type IV alpha 1 (COL4A1) gene mutation in a Chinese family with PADMAL. The index case was followed up for 6 years. Neuroimaging, whole-exome sequencing, skin biopsy, and pedigree analysis were performed. She initially presented with minor head injury at age 38. MRI brain showed chronic lacunar infarcts in the pons, left thalamus, and right centrum semiovale. Extensive workup was unremarkable except for a patent foramen ovale (PFO). Despite anticoagulation, PFO closure, and antiplatelet therapy, the patient had recurrent lacunar infarcts in the pons and deep white matter, as well as subcortical microhemorrhages. Whole-exome sequencing demonstrated a novel c.*34G > T mutation in the 3' untranslated region of COL4A1 gene. Skin biopsy subsequently demonstrated thickening of vascular basement membrane, proliferation of endothelial cells, and stenosis of vascular lumen. Three additional family members had gene testing and 2 of them were found to have the same heterozygous mutation. Of the 18 individuals in the pedigree of 3 generations, 12 had clinical and MRI evidence of PADMAL. The mechanisms of both ischemic and hemorrhagic stroke are likely the overexpression of COLT4A1 in the basement membrane and frugality of the vessel walls. Our findings suggest that the novel c.*34G > T mutation appears to have the same functional consequences as the previously reported COL4A1 gene mutations in patients with PADMAL and multi-infarct dementia of Swedish type.

Hereditary Cerebral Small Vessel Diseases and Stroke: A Guide for Diagnosis and Management

Cerebral small vessel diseases represent a frequent cause of stroke and cognitive or motor disability in adults. A small proportion of cerebral small vessel diseases is attributable to monogenic conditions. Since the characterization in the late 1990s of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, several other monogenic conditions leading to adult-onset ischemic or hemorrhagic stroke have been described. In this practical guide, we summarize the key features that should elicit the differential diagnosis of a hereditary cerebral small vessel diseases in adult stroke patients, describe the main clinical and imaging characteristics of the major hereditary cerebral small vessel diseases that can manifest as stroke, and provide general recommendations for the clinical management of affected patients and their relatives.

The role of basement membranes in cardiac biology and disease

Basement membranes are highly specialised extracellular matrix structures that within the heart underlie endothelial cells and surround cardiomyocytes and vascular smooth muscle cells. They generate a dynamic and structurally supportive environment throughout cardiac development and maturation by providing physical anchorage to the underlying interstitium, structural support to the tissue, and by influencing cell behaviour and signalling. While this provides a strong link between basement membrane dysfunction and cardiac disease, the role of the basement membrane in cardiac biology remains under-researched and our understanding regarding the mechanistic interplay between basement membrane defects and their morphological and functional consequences remain important knowledge-gaps. In this review we bring together emerging understanding of basement membrane defects within the heart including in common cardiovascular pathologies such as contractile dysfunction and highlight some key questions that are now ready to be addressed.

Genetic Analysis in a Swiss Cohort of Bilateral Congenital Cataract

Importance

Identification of geographic population-based differences in genotype and phenotype heterogeneity are important for targeted and patient-specific diagnosis and treatment, counseling, and screening strategies.

Objective

To report disease-causing variants and their detailed phenotype in patients with bilateral congenital cataract from a single center in Switzerland and thereby draw a genetic map and perform a genotype-phenotype comparison of this cohort.

Design, Setting, and Participants

This clinical and molecular-genetic cohort study took place through the collaboration of the Department of Ophthalmology at the University Hospital Zurich and the Institute of Medical Molecular Genetics, University of Zurich, Schlieren, Switzerland. Thirty-seven patients from 25 families with different types of bilateral congenital cataract were included. All participating family members received a comprehensive eye examination. Whole exome sequencing was performed in the index patients, followed by a filtering process to detect possible disease-associated variants in genes previously described in association with congenital cataract. Probable disease-causing variants were confirmed by Sanger sequencing in available family members. All data were collected from January 2018 to June 2020, and the molecular-genetic analyses were performed from January 2019 to July 2020.

Main Outcomes and Measures

Identification of the underlying genetic causes of bilateral congenital cataract, including novel disease-causing variants and phenotype correlation.

Results

Among the 37 patients (18 [49%] male and 19 [51%] female; mean [SD] age, 17.3 [15.9] years) from 25 families, pathogenic variants were detected in 20 families (80% detection rate), which included 13 novel variants in the following genes: BCOR, COL4A1, CRYBA2, CRYBB2, CRYGC, CRYGS, GJA3, MAF, NHS, and WFS1. Putative disease-causing variants were identified in 14 of 20 families (70%) as isolated cases and in 6 of 20 families (30%) with syndromic cases. A recessive variant in the CRYBB2 gene in a consanguineous family with 2 affected siblings showing a nuclear and sutural cataract was reported in contrast to previously published reports. In addition, the effect on splicing in a minigene assay of a novel splice site variant in the NHS gene (c.[719-2A>G]) supported the pathogenicity of this variant.

Conclusions and Relevance

This study emphasizes the importance of genetic testing of congenital cataracts. Known dominant genes need to be considered for recessive inheritance patterns. Syndromic types of cataract may be underdiagnosed in patients with mild systemic features.

A novel COL4A1 variant associated with recurrent epistaxis and glioblastoma

COL4A1-related disorders are characterized by a higher incidence of cerebral hemorrhage than other hereditary cerebral small vessel diseases. Accumulating data have shown broad phenotypic variations, and extracerebral hemorrhages have been linked to these disorders. Moreover, the coexistence of neural tumors has been described. Here, we report a Japanese family with a novel COL4A1 variant, including a patient with recurrent epistaxis and glioblastoma.

Brain MRI in Monogenic Cerebral Small Vessel Diseases: A Practical Handbook

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Monogenic cerebral small vessel diseases are a topic of growing interest, as several genes responsible have been recently described and new sequencing techniques such as Next generation sequencing are available. Brain imaging is a key exam in these diseases. First, since it is often the first exam performed, an MRI is key in selecting patients for genetic testing and for interpreting Next generation sequencing reports. In addition, neuroimaging can be helpful in describing the underlying pathological mechanisms involved in cerebral small vessel disease. With this review, we aim to provide Neurologists and Stroke physicians with an up-to date overview of the current neuroimaging knowledge on monogenic small vessel diseases.

Brain and Placental Pathology in Fetal COL4A1 Related Disease

INTRODUCTION

Although fetal brain injury due to COL4A1 gene mutation is well documented, fetal central nervous system (CNS) and placental histopathology lack description. We report CNS and placental pathology in fetal cases with symptomatic COL4A1 mutation.

METHODS

We retrieved four autopsy cases of COL4A1 related disease, confirmed by genetic sequencing after fetal brain injury was detected.

RESULTS

One case was a midgestation fetus with residua of ventricular zone hemorrhage and normal placental villi. Three cases were 30-32 week gestation fetuses: two demonstrated CNS small vessel thrombosis, with CNS injury. Both demonstrated high grade placental fetal vascular malperfusion (FVM). One additionally showed villous dysmorphism, the other demonstrated mild villous immaturity. The fetus whose placenta demonstrated high grade FVM was growth restricted. A fourth fetus demonstrated schizencephaly with a CNS arteriopathy with smooth muscle cell degeneration and cerebral infarcts; the placenta demonstrated severe villous dysmorphism and low grade FVM.

DISCUSSION

These cases confirm that small vessel disease is important in producing intracranial pathology in COL4A1mutation. We report an arteriopathy distinct from microvascular thrombosis and demonstrate that placental pathology is common in fetal COL4A1 related disease. This tentatively suggests that placental pathology may contribute to CNS abnormalities by affecting circulatory sufficiency.

Prevalence of COL4A1 and COL4A2 mutations in severe fetal multifocal hemorrhagic and/or ischemic cerebral lesions

OBJECTIVE

To establish the prevalence of COL4A1 and COL4A2 gene mutations in fetuses presenting with a phenotype suggestive of cerebral injury.

METHODS

This was a single-center retrospective analysis of all cases of fetal cerebral anomalies suggestive of COL4A1 or COL4A2 gene mutation over the period 2009-2018. Inclusion criteria were: (1) severe and/or multifocal hemorrhagic cerebral lesions; (2) multifocal ischemic-hemorrhagic cerebral lesions. These anomalies could be of different ages and associated with schizencephaly or porencephaly. Between fetuses with and those without a mutation, we compared gestational age at the time of diagnosis, parity and fetal gender.

RESULTS

Among the 956 cases of cerebral anomaly diagnosed in our center during the 10-year study period, 18 fetuses were identified for inclusion. A pathogenic COL4A1 gene mutation was found in five of these cases, among which four were de-novo mutations. A variant of unknown significance was found in four fetuses: in the COL4A1 gene in one case and in the COL4A2 gene in three cases. No COL4A1 or COL4A2 mutation was found in the remaining nine fetuses. The median (interquartile range) gestational age at diagnosis was significantly lower in cases with a mutation (24 (22-26) weeks) than in cases without a mutation (32 (29.5-34.5) weeks) (P = 0.03).

CONCLUSIONS

A phenotype suggestive of cerebral injury was found in 18 of the 956 (1.9%) cases in our population, in 28% of which there was an associated COL4A1 or COL4A2 mutation. COL4A1 and COL4A2 gene mutations should be sought systematically in cases of severe and/or multifocal hemorrhagic or ischemic-hemorrhagic cerebral lesions, with or without schizencephaly or porencephaly. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Identification of fibronectin 1 as a candidate genetic modifier in a Col4a1 mutant mouse model of Gould syndrome

Collagen type IV alpha 1 and alpha 2 (COL4A1 and COL4A2) are major components of almost all basement membranes. COL4A1 and COL4A2 mutations cause a multisystem disorder that can affect any organ but typically involves the cerebral vasculature, eyes, kidneys and skeletal muscles. In recent years, patient advocacy and family support groups have united under the name of Gould syndrome. The manifestations of Gould syndrome are highly variable, and animal studies suggest that allelic heterogeneity and genetic context contribute to the clinical variability. We previously characterized a mouse model of Gould syndrome caused by a Col4a1 mutation in which the severities of ocular anterior segment dysgenesis (ASD), myopathy and intracerebral hemorrhage (ICH) were dependent on genetic background. Here, we performed a genetic modifier screen to provide insight into the mechanisms contributing to Gould syndrome pathogenesis and identified a single locus [modifier of Gould syndrome 1 (MoGS1)] on Chromosome 1 that suppressed ASD. A separate screen showed that the same locus ameliorated myopathy. Interestingly, MoGS1 had no effect on ICH, suggesting that this phenotype could be mechanistically distinct. We refined the MoGS1 locus to a 4.3 Mb interval containing 18 protein-coding genes, including Fn1, which encodes the extracellular matrix component fibronectin 1. Molecular analysis showed that the MoGS1 locus increased Fn1 expression, raising the possibility that suppression is achieved through a compensatory extracellular mechanism. Furthermore, we found evidence of increased integrin-linked kinase levels and focal adhesion kinase phosphorylation in Col4a1 mutant mice that is partially restored by the MoGS1 locus, implicating the involvement of integrin signaling. Taken together, our results suggest that tissue-specific mechanistic heterogeneity contributes to the variable expressivity of Gould syndrome and that perturbations in integrin signaling may play a role in ocular and muscular manifestations.

COL4A1 mutation in an Indian child presenting as 'Cerebral Palsy' mimic

The COL4A1 gene (COL4A1) plays an important role in vascular basement membrane function and pathogenic mutations have been reported in mice and humans. The gene is expressed mainly in the human brain, eyes and kidneys. Pathogenic mutations result in a vast array of manifestations that can present throughout life including the foetal period. We present a case of an 11-year-old girl with right hemiparesis, congenital cataracts, epilepsy and magnetic resonance imaging (MRI) brain findings with a pathogenic COL4A1 mutation. Many of her clinical features are similar to those of a non-genetic cause of cerebral palsy highlighting the difficulties and delays in making this genetic diagnosis.

Dynamic transcriptome landscape in the song nucleus HVC between juvenile and adult zebra finches

Male juvenile zebra finches learn to sing by imitating songs of adult males early in life. The development of the song control circuit and song learning and maturation are highly intertwined processes, involving gene expression, neurogenesis, circuit formation, synaptic modification, and sensory-motor learning. To better understand the genetic and genomic mechanisms underlying these events, we used RNA-Seq to examine genome-wide transcriptomes in the song control nucleus HVC of male juvenile (45 d) and adult (100 d) zebra finches. We report that gene groups related to axon guidance, RNA processing, lipid metabolism, and mitochondrial functions show enriched expression in juvenile HVC compared to the rest of the brain. As juveniles mature into adulthood, massive gene expression changes occur. Expression of genes related to amino acid metabolism, cell cycle, and mitochondrial function is reduced, accompanied by increased and enriched expression of genes with synaptic functions, including genes related to G-protein signaling, neurotransmitter receptors, transport of small molecules, and potassium channels. Unexpectedly, a group of genes with immune system functions is also developmentally regulated, suggesting potential roles in the development and functions of HVC. These data will serve as a rich resource for investigations into the development and function of a neural circuit that controls vocal behavior.

Fetal brain small vessel disease 1 caused by a novel mutation in the COL4A1 gene

A singleton fetus was referred to fetal magnetic resonance imaging (MRI) at 25 weeks due to mild ventriculomegaly and an abnormal fetal echocardiogram showing cardiomegaly, right ventricular hypertrophy and tricuspid insufficiency. Patchy areas of ischemic infarction, extensive subacute and chronic hemorrhage not respecting vascular territories, encephaloclastic cysts and closed lip schizencephaly were identified. Cataract was detected postnatally. The anomalies were caused by a pathogenic mutation (c.353 G>A; p.G118D) in the COL4A1 gene. The phenotype seen in this case, i.e. small vessel cerebral disease with or without ocular anomalies caused by COL4A1 mutations, is likely an underrecognized cause of perinatal stroke. The pattern of abnormalities reported herein should prompt strong consideration for diagnosis and molecular testing.

The epileptology of Aicardi-Goutières syndrome: electro-clinical-radiological findings

OBJECTIVE

Although epileptic seizures occur in approximately a quarter of patients with Aicardi-Goutières syndrome (AGS), their phenotypic and electrophysiological characterization remains elusive. The aim of our study was to characterize epilepsy phenotypes and electroencephalographic (EEG) patterns in AGS and look for possible correlations with clinical, genetic and neuroradiological features.

METHODS

We selected patients with an established AGS diagnosis followed at three Italian reference centers. Medical records, EEGs and MRI/CT findings were reviewed. EEGs were independently and blindly reviewed by three board-certified pediatric epileptologists. Chi square and Fisher's exact tests were used to test associations between epilepsy and EEG feature categories and clinical, radiological and genetic variables.

RESULTS

Twenty-seven patients were enrolled. We reviewed 63 EEGs and at least one brain MRI scan per patient. Epilepsy, mainly in the form of epileptic spasms and focal seizures, was present in 37 % of the cohort; mean age at epilepsy onset was 9.5 months (range 1-36). The presence of epilepsy was associated with calcification severity (p = 0.016) and startle reactions (p = 0.05). Organization of EEG electrical activity appeared to be disrupted or markedly disrupted in 73 % of cases. Severe EEG disorganization correlated with microcephaly (p < 0.001) and highly abnormal MRI T2-weighted signal intensity in white matter (p = 0.022). Physiological organization of the EEG was found to be better preserved during sleep (87 %) than wakefulness (38 %). Focal slow activity was recorded in more than one third of cases. Fast activity, either diffuse or with frontal location, was more frequent in the awake state (78 %) than in sleep (50 %). Interictal epileptiform discharges (IEDs) were present in 33 % of awake and 45 % of sleep recordings. IEDs during sleep were associated with a higher risk of a epileptic seizures (p = 0.008).

SIGNIFICANCE

The hallmarks of EEG recordings in AGS were found to be: disruption of electrical organization, the presence of focal slow and fast activity, and the presence of IEDs, both in patients with and in those without epilepsy. The associations between epilepsy and calcification and between EEG pattern and the finding of a highly abnormal white matter T2 signal intensity suggest a common anatomical correlate. However, the complex anatomical-electroclinical basis of AGS-related epilepsy still requires further elucidation.

Neuropathology of genetically defined malformations of cortical development-A systematic literature review

AIMS

Malformations of cortical development (MCD) include a heterogeneous spectrum of clinical, imaging, molecular and histopathological entities. While the understanding of genetic causes of MCD has improved with the availability of next-generation sequencing modalities, genotype-histopathological correlations remain limited. This is the first systematic review of molecular and neuropathological findings in patients with MCD to provide a comprehensive overview of the literature.

METHODS

A systematic review was performed between November 2019 and February 2020. A MEDLINE search was conducted for 132 genes previously linked to MCD in order to identify studies reporting macroscopic and/or microscopic findings in patients with a confirmed genetic cause.

RESULTS

Eighty-one studies were included in this review reporting neuropathological features associated with pathogenic variants in 46 genes (46/132 genes, 34.8%). Four groups emerged, consisting of (1) 13 genes with well-defined histological-genotype correlations, (2) 27 genes for which neuropathological reports were limited, (3) 5 genes with conflicting neuropathological features, and (4) 87 genes for which no histological data were available. Lissencephaly and polymicrogyria were reported most frequently. Associated brain malformations were variably present, with abnormalities of the corpus callosum as most common associated feature.

CONCLUSIONS

Neuropathological data in patients with MCD with a defined genetic cause are available only for a small number of genes. As each genetic cause might lead to unique histopathological features of MCD, standardised thorough neuropathological assessment and reporting should be encouraged. Histological features can help improve the understanding of the pathogenesis of MCD and generate hypotheses with impact on further research directions.

Network for Therapy in Rare Epilepsies (NETRE): Lessons From the Past 15 Years

Background: In 2005, Network for Therapy in Rare Epilepsies (NETRE)-was initiated in order to share treatment experiences among clinicians in patients with rare epilepsies. Here we describe the structure of the rapidly growing NETRE and summarize some of the findings of the last 15 years. Methodology/Structure of NETRE: NETRE is organized in distinct groups (currently >270). Starting point is always a patient with a rare epilepsy/ epileptic disorder. This creates a new group, and next, a medical coordinator is appointed. The exchange of experiences is established using a data entry form, which the coordinator sends to colleagues. The primary aim is to exchange experiences (retrospectively, anonymously, MRI results also non-anonymously) of the epilepsy treatment as well as on clinical presentation and comorbidities NETRE is neither financed nor sponsored. Results: Some of the relevant results: (1) first description of FIRES as a new epilepsy syndrome and its further investigation, (2) in SCN2A, the assignment to gain- vs. loss-of-function mutations has a major impact on clinical decisions to use or avoid treatment with sodium channel blockers, (3) the important aspect of avoiding overtreatment in CDKL5 patients, due to loss of effects of anticonvulsants after 12 months, (4) pathognomonic MRI findings in FOXG1 patients, (5) the first description of pathognomonic chewing-induced seizures in SYNGAP1 patients, and the therapeutic effect of statins as anticonvulsant in these patients, (6) the phenomenon of another reflex epilepsy-bathing epilepsy associated with a SYN1 mutation. Of special interest is also a NETRE group following twins with genetic and/or structural epilepsies [including vanishing-twin-syndrome and twin-twin-transfusion syndrome) [= "Early Neuroimpaired Twin Entity" (ENITE)]. Discussion and Perspective: NETRE enables clinicians to quickly exchange information on therapeutic experiences in rare diseases with colleagues at an international level. For both parents and clinicians/scientist this international exchange is both reassuring and helpful. In collaboration with other groups, personalized therapeutic approaches are sought, but the present limitations of currently available therapies are also highlighted. Presently, the PATRE Project (PATient based phenotyping and evaluation of therapy for Rare Epilepsies) is commencing, in which information on therapies will be obtained directly from patients and their caregivers.

Intracerebral hemorrhage in a neonate with an intragenic COL4A2 duplication

Intracerebral hemorrhage is rare in term born neonates. Besides several non‐genetic risk factors, pathogenic variants in COL4A1 and COL4A2 have been described to play a role in the pathophysiology of neonatal intracerebral hemorrhage. To the best of our knowledge, no intragenic COL4A2 duplications have been reported in humans to date. We report a neonate with intracerebral hemorrhage and a de novo intragenic COL4A2 duplication. Although it is not clear yet whether this genetic factor fully explains the clinical phenotype, it may have contributed at least as a risk factor for cerebral hemorrhage. Screening for intragenic COL4A1 and COL4A2 duplications as part of collagen IV diagnostics should be considered as part of the fetal and neonatal work‐up for unexplained cerebral hemorrhages and to collect more evidence of the pathogenicity of this genetic mechanism.

The spectrum of brain malformations and disruptions in twins

Twins have an increased risk for congenital malformations and disruptions, including defects in brain morphogenesis. We analyzed data on brain imaging, zygosity, sex, and fetal demise in 56 proband twins and 7 less affected co-twins with abnormal brain imaging and compared them to population-based data and to a literature series. We separated our series into malformations of cortical development (MCD, N = 39), cerebellar malformations without MCD (N = 13), and brain disruptions (N = 11). The MCD group included 37/39 (95%) with polymicrogyria (PMG), 8/39 (21%) with pia-ependymal clefts (schizencephaly), and 15/39 (38%) with periventricular nodular heterotopia (PNH) including 2 with PNH but not PMG. Cerebellar malformations were found in 19 individuals including 13 with a cerebellar malformation only and another 6 with cerebellar malformation and MCD. The pattern varied from diffuse cerebellar hypoplasia to classic Dandy-Walker malformation. Brain disruptions were seen in 11 individuals with hydranencephaly, porencephaly, or white matter loss without cysts. Our series included an expected statistically significant excess of monozygotic (MZ) twin pairs (22/41 MZ, 54%) compared to population data (482/1448 MZ, 33.3%; p = .0110), and an unexpected statistically significant excess of dizygotic (DZ) twins (19/41, 46%) compared to the literature cohort (1/46 DZ, 2%; p < .0001. Recurrent association with twin-twin transfusion syndrome, intrauterine growth retardation, and other prenatal factors support disruption of vascular perfusion as the most likely unifying cause.

Extracellular Control of Radial Glia Proliferation and Scaffolding During Cortical Development and Pathology

During the development of the cortex, newly generated neurons migrate long-distances in the expanding tissue to reach their final positions. Pyramidal neurons are produced from dorsal progenitors, e.g., radial glia (RGs) in the ventricular zone, and then migrate along RG processes basally toward the cortex. These neurons are hence dependent upon RG extensions to support their migration from apical to basal regions. Several studies have investigated how intracellular determinants are required for RG polarity and subsequent formation and maintenance of their processes. Fewer studies have identified the influence of the extracellular environment on this architecture. This review will focus on extracellular factors which influence RG morphology and pyramidal neuronal migration during normal development and their perturbations in pathology. During cortical development, RGs are present in different strategic positions: apical RGs (aRGs) have their cell bodies located in the ventricular zone with an apical process contacting the ventricle, while they also have a basal process extending radially to reach the pial surface of the cortex. This particular conformation allows aRGs to be exposed to long range and short range signaling cues, whereas basal RGs (bRGs, also known as outer RGs, oRGs) have their cell bodies located throughout the cortical wall, limiting their access to ventricular factors. Long range signals impacting aRGs include secreted molecules present in the embryonic cerebrospinal fluid (e.g., Neuregulin, EGF, FGF, Wnt, BMP). Secreted molecules also contribute to the extracellular matrix (fibronectin, laminin, reelin). Classical short range factors include cell to cell signaling, adhesion molecules and mechano-transduction mechanisms (e.g., TAG1, Notch, cadherins, mechanical tension). Changes in one or several of these components influencing the RG extracellular environment can disrupt the development or maintenance of RG architecture on which neuronal migration relies, leading to a range of cortical malformations. First, we will detail the known long range signaling cues impacting RG. Then, we will review how short range cell contacts are also important to instruct the RG framework. Understanding how RG processes are structured by their environment to maintain and support radial migration is a critical part of the investigation of neurodevelopmental disorders.

Expanding the phenotype of COL4A1-related disorders-Four novel variants

OBJECTIVE

COL4A1 variant causes severe central nervous system (CNS) anomalies, including hydranencephaly. However, the pathogenic mechanism underlying the COL4A1 phenotype remains unclear. Here, we report de novo COL4A1 variants in four Japanese patients with typical or rare CNS involvement and exhibiting diverse phenotypes.

METHODS

We identified and enrolled four patients with white matter abnormalities and cerebral structural defects suggestive of cerebrovascular disease. Genetic analysis was performed using panel sequencing.

RESULTS

All the patients were perinatally asymptomatic during the infantile period but exhibited developmental delay and growth retardation later. All the patients exhibited CNS symptoms, including psychomotor disability, spastic paralysis, and epilepsy. Brain magnetic resonance imaging revealed hydranencephaly (n = 1), ventriculomegaly (n = 4) associated with cerebral hemorrhage, and atretic encephalocele (n = 1). Three patients had developed congenital cataract, while two had hematuria. We identified two COL4A1 missense variants [exon32:c.2555G > A p.(Gly852Asp), exon40:c.3407G > A p.(Gly1136Asp)] and two in frame variants [exon32:c.2603_2609delinsATCCTGA p.(Ala868_Gly870delinsAspProGlu), exon36:c.3054delinsTGTAGAT p.(Leu1018delinsPheValAsp)]. The in frame variants were associated with severe CNS anomalies, hydranencephaly, and severe ventriculomegaly. Atretic encephalocele has never been reported in individuals with COL4A1 variants.

CONCLUSIONS

Our findings suggest that COL4A1 variants cause variable CNS symptoms. Association between clinical phenotypes and each COL4A1 variant would clarify their underlying etiologies.

p.Gly743Val Mutation in COL4A1 Is Responsible for Familial Porencephaly and Severe Hypermetropia

COL4A1 is an essential component for basal membrane stability. Exon mutations of the COL4A1 genes are responsible for a broad spectrum of cerebral, ocular, and systemic manifestations. We describe here the phenotype of a likely pathogenic gene variant, p.Gly743Val, which is responsible for a missense mutation in the COL4A1 gene exon 30 in a three generation family with severe hypermetropia and highly penetrant porencephaly in the absence of systemic manifestations. This report highlights both the broad spectrum of COL4A1 mutations and the yield of testing the COL4A1 gene in familial ophthalmological and brain disorders.

International consensus recommendations on the diagnostic work-up for malformations of cortical development

Malformations of cortical development (MCDs) are neurodevelopmental disorders that result from abnormal development of the cerebral cortex in utero. MCDs place a substantial burden on affected individuals, their families and societies worldwide, as these individuals can experience lifelong drug-resistant epilepsy, cerebral palsy, feeding difficulties, intellectual disability and other neurological and behavioural anomalies. The diagnostic pathway for MCDs is complex owing to wide variations in presentation and aetiology, thereby hampering timely and adequate management. In this article, the international MCD network Neuro-MIG provides consensus recommendations to aid both expert and non-expert clinicians in the diagnostic work-up of MCDs with the aim of improving patient management worldwide. We reviewed the literature on clinical presentation, aetiology and diagnostic approaches for the main MCD subtypes and collected data on current practices and recommendations from clinicians and diagnostic laboratories within Neuro-MIG. We reached consensus by 42 professionals from 20 countries, using expert discussions and a Delphi consensus process. We present a diagnostic workflow that can be applied to any individual with MCD and a comprehensive list of MCD-related genes with their associated phenotypes. The workflow is designed to maximize the diagnostic yield and increase the number of patients receiving personalized care and counselling on prognosis and recurrence risk.

Precision medicine and therapies of the future

Precision medicine in the epilepsies has gathered much attention, especially with gene discovery pushing forward new understanding of disease biology. Several targeted treatments are emerging, some with considerable sophistication and individual‐level tailoring. There have been rare achievements in improving short‐term outcomes in a few very select patients with epilepsy. The prospects for further targeted, repurposed, or novel treatments seem promising. Along with much‐needed success, difficulties are also arising. Precision treatments do not always work, and sometimes are inaccessible or do not yet exist. Failures of precision medicine may not find their way to broader scrutiny. Precision medicine is not a new concept: It has been boosted by genetics and is often focused on genetically determined epilepsies, typically considered to be driven in an individual by a single genetic variant. Often the mechanisms generating the full clinical phenotype from such a perceived single cause are incompletely understood. The impact of additional genetic variation and other factors that might influence the clinical presentation represent complexities that are not usually considered. Precision success and precision failure are usually equally incompletely explained. There is a need for more comprehensive evaluation and a more rigorous framework, bringing together information that is both necessary and sufficient to explain clinical presentation and clinical responses to precision treatment in a precision approach that considers the full picture not only of the effects of a single variant, but also of its genomic and other measurable environment, within the context of the whole person. As we may be on the brink of a treatment revolution, progress must be considered and reasoned: One possible framework is proposed for the evaluation of precision treatments.

Revealing hidden genetic diagnoses in the ocular anterior segment disorders

Purpose

Ocular anterior segment disorders (ASDs) are clinically and genetically heterogeneous, and genetic diagnosis often remains elusive. In this study, we demonstrate the value of a combined analysis protocol using phenotypic, genomic, and pedigree structure data to achieve a genetic conclusion.

Methods

We utilized a combination of chromosome microarray, exome sequencing, and genome sequencing with structural variant and trio analysis to investigate a cohort of 41 predominantly sporadic cases.

Results

We identified likely causative variants in 54% (22/41) of cases, including 51% (19/37) of sporadic cases and 75% (3/4) of cases initially referred as familial ASD. Two-thirds of sporadic cases were found to have heterozygous variants, which in most cases were de novo. Approximately one-third (7/22) of genetic diagnoses were found in rarely reported or recently identified ASD genes including PXDN, GJA8, COL4A1, ITPR1, CPAMD8, as well as the new phenotypic association of Axenfeld–Rieger anomaly with a homozygous ADAMTS17 variant. The remainder of the variants were in key ASD genes including FOXC1, PITX2, CYP1B1, FOXE3, and PAX6.

Conclusions

We demonstrate the benefit of detailed phenotypic, genomic, variant, and segregation analysis to uncover some of the previously “hidden” heritable answers in several rarely reported and newly identified ocular ASD-related disease genes.

Monogenic cerebral small-vessel diseases: diagnosis and therapy. Consensus recommendations of the European Academy of Neurology

BACKGROUND AND PURPOSE

Guidelines on monogenic cerebral small-vessel disease (cSVD) diagnosis and management are lacking. Endorsed by the Stroke and Neurogenetics Panels of the European Academy of Neurology, a group of experts has provided recommendations on selected monogenic cSVDs, i.e. cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), autosomal dominant High Temperature Requirement A Serine Peptidase 1 (HTRA1), cathepsin-A-related arteriopathy with strokes and leukoencephalopathy (CARASAL), pontine autosomal dominant microangiopathy and leukoencephalopathy (PADMAL), Fabry disease, mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) and type IV collagen (COL4)A1/2.

METHODS

We followed the Delphi methodology to provide recommendations on several unanswered questions related to monogenic cSVD, including genetic testing, clinical and neuroradiological diagnosis, and management.

RESULTS

We have proposed 'red-flag' features suggestive of a monogenic disease. General principles applying to the management of all cSVDs and specific recommendations for the individual forms of monogenic cSVD were agreed by consensus.

CONCLUSIONS

The results provide a framework for clinicians involved in the diagnosis and management of monogenic cSVD. Further multicentre observational and treatment studies are still needed to increase the level of evidence supporting our recommendations.

Phenotypic characterization of COL4A1-related West syndrome

Collagen type IV, alpha-1 (COL4A1) variants can cause cerebrovascular diseases, such as porencephaly and cerebral hemorrhage, in addition to other autosomal dominant hereditary diseases. Patients with COL4A1 variants can present with epilepsy, most commonly focal epilepsy. In this paper, we present five patients, three of whom were examined by the authors, and two who were previously reported. Clinically, these five patients were characterized by the presence of West syndrome (WS), periventricular leukomalacia (PVL), and microcephaly, but none had a history of premature birth or hypoxic ischemic encephalopathy (HIE). Genetic testing results indicated that all patients had heterozygous variants of COL4A1. Genetic testing for the COL4A1 variants should be considered when a patient without a history of prematurity or HIE develops WS with PVL and microcephaly.

Heritable and non-heritable uncommon causes of stroke

Despite intensive investigations, about 30% of stroke cases remains of undetermined origin. After exclusion of common causes of stroke, there is a number of rare heritable and non-heritable conditions, which often remain misdiagnosed, that should be additionally considered in the diagnosis of cryptogenic stroke. The identification of these diseases requires a complex work up including detailed clinical evaluation for the detection of systemic symptoms and signs, an adequate neuroimaging assessment and a careful family history collection. The task becomes more complicated by phenotype heterogeneity since stroke could be the primary or unique manifestation of a syndrome or represent just a manifestation (sometimes minor) of a multisystem disorder. The aim of this review paper is to provide clinicians with an update on clinical and neuroradiological features and a set of practical suggestions for the diagnostic work up and management of these uncommon causes of stroke. The identification of these stroke causes is important to avoid inappropriate and expensive diagnostic tests, to establish appropriate management measures, including presymptomatic testing, genetic counseling, and, if available, therapy. Therefore, physicians should become familiar with these diseases to provide future risk assessment and family counseling.

Vasospasm Following Hemispherectomy: A Case Report of a Novel Complication

BACKGROUND

Hemispherectomy has been shown to be successful in treating medically intractable epilepsy, with favorable seizure-free outcomes. However, the procedure is technically challenging with high rates of in-hospital complications. We present a unique case of functional hemispherectomy complicated by diffuse cerebral vasospasm and subsequent death in a patient with COL4A1 gene mutation.

CASE DESCRIPTION

A 17-year-old boy presented with right hemispheric epilepsy and a previously diagnosed autosomal dominant heterozygous COL4A1 gene mutation (c.4380T>G;p.Cys1460Trp). Functional hemispherectomy was performed without complications. On postoperative day 8, he developed an acute decline in neurologic status requiring urgent intubation for airway protection. Magnetic resonance imaging revealed areas of restricted diffusion throughout bilateral hemispheres that was explained by severe vasospasm and minimal cerebral blood flow seen on cerebral angiography. Intra-arterial calcium channel blocker infusion and balloon angioplasty were attempted without improvement in perfusion. With a worsening clinical picture, he was transitioned to comfort care and died.

CONCLUSIONS

This is the first report in the literature describing global vasospasm and delayed cerebral ischemia following hemispherectomy in a patient carrying COL4A1 gene mutation. We postulate that his COL4A1 gene mutation might have resulted in this exaggerated vasospasm despite minimal residual postoperative subarachnoid hemorrhage burden. This hypothesis needs to be studied in animal models of this genetic disorder.

COL4A1-related autosomal recessive encephalopathy in 2 Turkish children

OBJECTIVE

This study presents the neurologic phenotypes of 2 brothers with a novel homozygous COL4A1 mutation that was identified in a large Turkish consanguineous cohort of neurogenetic diseases.

METHODS

Whole-exome sequencing and bioinformatic analysis of consanguineous families with children affected by early-onset, neurogenetic disorders was performed using the RD-Connect Genome-Phenome Analysis Platform. We also performed clinical, EEG, and neuroimaging analyses in unaffected siblings and parents.

RESULTS

We have identified a homozygous missense mutation in COL4A1 (p.Gly1278Ser, NM_001845.5:c.3832G>T) in 2 siblings affected by small vessel brain disease with periventricular leukoencephalopathy and ocular defects. Presenting symptoms included mild weakness, hemiparetic gait, pyramidal findings, and seizures, whereas their intellectual and behavioral functions were normal. Both parents and 5 of the siblings (3 boys and 2 girls) were heterozygous for the variant. They did not show any clinical or laboratory signs of small vessel disease.

CONCLUSIONS

COL4A1 has previously been associated with dominant small vessel disease of the brain and other organs, manifesting with high penetrance in heterozygous mutation carriers. Our findings provide evidence that COL4A1-related encephalopathy can be inherited in an autosomal recessive manner, which is important for counseling, prognosis, and treatment. Genotype-phenotype correlations remain to be established.

Clinical utility of genetic testing in 201 preschool children with inherited eye disorders

Purpose

A key property to consider in all genetic tests is clinical utility, the ability of the test to influence patient management and health outcomes. Here we assess the current clinical utility of genetic testing in diverse pediatric inherited eye disorders (IEDs).

Methods

Two hundred one unrelated children (0–5 years old) with IEDs were ascertained through the database of the North West Genomic Laboratory Hub, Manchester, UK. The cohort was collected over a 7-year period (2011–2018) and included 74 children with bilateral cataracts, 8 with bilateral ectopia lentis, 28 with bilateral anterior segment dysgenesis, 32 with albinism, and 59 with inherited retinal disorders. All participants underwent panel-based genetic testing.

Results

The diagnostic yield of genetic testing for the cohort was 64% (ranging from 39% to 91% depending on the condition). The test result led to altered management (including preventing additional investigations or resulting in the introduction of personalized surveillance measures) in 33% of probands (75% for ectopia lentis, 50% for cataracts, 33% for inherited retinal disorders, 7% for anterior segment dysgenesis, 3% for albinism).

Conclusion

Genetic testing helped identify an etiological diagnosis in the majority of preschool children with IEDs. This prevented additional unnecessary testing and provided the opportunity for anticipatory guidance in significant subsets of patients.

De novo p.G696S mutation in COL4A1 causes intracranial calcification and late-onset cerebral hemorrhage: A case report and review of the literature

BACKGROUND

The collagen type IV alpha 1 chain (COL4A1) is an essential component of the basement membrane in small vessels. Pathogenic variants in COL4A1 cause perinatal cerebral hemorrhages in an autosomal-dominant fashion. However, little is known about the long-term outcomes of patients with mildly affecting COL4A1 mutations.

CASE REPORT

We report a 17-year-old boy, who presented with recurrent intracranial hemorrhages in the periventricular white matter. He had been followed-up as a child with cerebral palsy bearing intracranial calcifications, developmental delay and epilepsy. Screening tests in infancy provided negative results for intrauterine infections. Severe motor and cognitive deficits persisted after admission. Carbazochrome was introduced on day 19 of admission, which appeared to prevent extension and reactivation of cerebral hemorrhages for over 6 months after discharge.

RESULTS

Targeted sequencing of NOTCH3 and TREX1 excluded causal mutations in these genes. The whole-exome sequencing revealed that he carried a de novo mutation in COL4A1 (p.Gly696Ser). An overview of the literature for 345 cases with COL4A1 mutations supported evidence that p.Gly696Ser is associated with the unique phenotype of late-onset hemorrhage among patients with COL4A1-associated cerebral angiopathy.

CONCLUSIONS

This case first demonstrates that infants with COL4A1-associated leukoencephalopathy and calcifications have a risk for developing the rupture of small vessels in the cerebral white matter after 10 years of age.

Collagens and elastin genetic variations and their potential role in aging-related diseases and longevity in humans

Collagens and elastin are 'building blocks' of tissues and extracellular matrix. Mutations in these proteins cause severe congenital syndromes. Adverse genetic variations may accelerate the aging process in adults contributing to premature morbidity, disability and/or mortality. Favorable variants may contribute to longevity and/or healthy aging, but this is much less studied. We reviewed the association between variation in the genes of collagens and elastin and premature aging, accelerated aging, age-related diseases and/or frailty; and the association between genetic variation in those and longevity and/or healthy aging in humans. A systematic search was conducted in MEDLINE and other online databases (OMIM, Genetics Home Reference, Orphanet, ClinVar). Results suggest that genetic variants lead to aging phenotypes of known congenital disease, but also to association with common age-related diseases in adults without known congenital disease. This may be due to the variable penetrance and expressivity of many variants. Some collagen variants have been associated with longevity or healthy aging. A limitation is that most studies had <1000 participants and their criterion for statistical significance was p < 0.05. Results highlight the importance of adopting a lifecourse approach to the study of the genomics of aging. Gerontology can help with new methodologies that operationalize biological aging.

Muscle regulates mTOR dependent axonal local translation in motor neurons via CTRP3 secretion: implications for a neuromuscular disorder, spinal muscular atrophy

Spinal muscular atrophy (SMA) is an inherited neuromuscular disorder, which causes dysfunction/loss of lower motor neurons and muscle weakness as well as atrophy. While SMA is primarily considered as a motor neuron disease, recent data suggests that survival motor neuron (SMN) deficiency in muscle causes intrinsic defects. We systematically profiled secreted proteins from control and SMN deficient muscle cells with two combined metabolic labeling methods and mass spectrometry. From the screening, we found lower levels of C1q/TNF-related protein 3 (CTRP3) in the SMA muscle secretome and confirmed that CTRP3 levels are indeed reduced in muscle tissues and serum of an SMA mouse model. We identified that CTRP3 regulates neuronal protein synthesis including SMN via mTOR pathway. Furthermore, CTRP3 enhances axonal outgrowth and protein synthesis rate, which are well-known impaired processes in SMA motor neurons. Our data revealed a new molecular mechanism by which muscles regulate the physiology of motor neurons via secreted molecules. Dysregulation of this mechanism contributes to the pathophysiology of SMA.

Cortical malformations and COL4A1 mutation: Three new cases

AIM

The COL4A1 gene (13q34) encodes the α1 chain of type IV collagen, a crucial component of the basal membrane. COL4A1 mutations have been identified as a cause of a multisystem disease. Brain MRI in COL4A1-mutated patients typically shows vascular abnormalities and white matter lesions. Cortical malformations (specifically schizencephaly) have also recently been described in these patients, suggesting that these, too, could be part of the phenotypic spectrum of COL4A1 mutations. The aim of our work was to retrospectively evaluate COL4A1-mutated subjects diagnosed at our centers in order to assess the frequency and define the type of cortical malformations encountered in these individuals.

METHOD

We retrospectively reviewed MRI data of 18 carriers of COL4A1 mutations diagnosed in our centers between 2010 and 2016.

RESULTS

We identified polymicrogyria in two patients, and schizencephaly in the mother of a further patient.

INTERPRETATION

Our findings confirm that cortical malformations should be considered to fall within the phenotypic spectrum of COL4A1 mutations and show that not only schizencephaly but also polymicrogyria can also be found in mutated individuals. Although further studies are needed to clarify the underlying pathogenetic mechanism, independently of this, the timing of the brain damage could be the crucial factor determining the type of lesion.

Perinatal stroke syndromes: Similarities and diversities in aetiology, outcome and management

With a birth-prevalence of 37-67/100,000 (mostly term-born), perinatal stroke encompasses distinct disease-states with diverse causality, mechanism, time of onset, mode of presentation and outcome. Neonatal primary haemorrhagic stroke and ischemic events (also divided into neonatal arterial ischemic stroke and neonatal cerebral sinus venous thrombosis) that manifest soon after birth are distinguished from presumed perinatal - ischemic or haemorrhagic - stroke. Signs of the latter become apparent only beyond the neonatal period, most often with motor asymmetry or milestones delay, and occasionally with seizures. Acute or remote MRI defines the type of stroke and is useful for prognosis. Acute care relies on homeostatic maintenance. Seizures are often self-limited and anticonvulsant agents might be discontinued before discharge. Prolonged anticoagulation for a few weeks is an option in some cases of sinovenous thrombosis. Although the risk of severe impairment is low, many children develop mild to moderate multimodal developmental issues that require a multidisciplinary approach.