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

European Academy of Neurology: First 10 years

The European Academy of Neurology (EAN) was founded in May 2014 as the scientific society of all neurologists and all national neurological societies in Europe. The creation of EAN was based on the conscious decision of two predecessor societies (the European Federation of Neurological Societies and the European Neurological Society) to have a unique society for this continent with its 53 countries according to the World Health Organization and with the EU as the most important continental political decision level. In this report, the important milestones and the motivations of the decision-makers during the first 10 years are described. The development of the annual congress, the broad educational agenda, and the scientific groundwork including the European guidelines for the practise of neurology are described. Collaboration with and work for the national neurological societies is an important task for EAN. The political representation of neurology in Brussels and collaboration with the scientific societies of neighbouring medical disciplines and patient organizations are other major tasks on the agenda of the organization. EAN's goal is to reduce the burden of neurological diseases and to be the "home of neurology" in Europe for physicians, patients, and society. EAN communicates and interacts with its members, patients, partners, politicians, and the public through different channels. EAN is the owner of the scientifically independent European Journal of Neurology. EAN is based in Vienna, where its head office is located, but is also strongly represented in Brussels.

CADA-PRO: A Patient Questionnaire Measuring Key Cognitive, Motor, Emotional, and Behavioral Outcomes in CADASIL

BACKGROUND

Cerebral small vessel disease (cSVD) of ischemic type, either sporadic or genetic, as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), can impact the quality of daily life on various cognitive, motor, emotional, or behavioral aspects. No instrument has been developed to measure these outcomes from the patient's perspective. We thus aimed to develop and validate a patient-reported questionnaire.

METHODS

In a development study, 79 items were generated by consensus between patients, family representatives, and cSVD experts. A first sample of patients allowed assessing the feasibility (missing data, floor and ceiling effect, and acceptability), internal consistency, and dimensionality of a first set of items. Thereafter, in a validation study, we tested a reduced version of the item set in a larger sample to assess the feasibility, internal consistency, dimensionality, test-retest reliability, concurrent validity, and sensitivity to change.

RESULTS

The scale was developed in 44 patients with cSVD and validated in a second sample of 89 individuals (including 43 patients with CADASIL and 46 with another cSVD). The final CADASIL Patient-Reported Outcome scale comprised 18 items covering 4 categories of consequences (depression/anxiety, attention/executive functions, motor, and daily activities) of the disease. The proportion of missing data was low, and no item displayed a major floor or ceiling effect. Both the internal consistency and test-retest reliability were good (Cronbach alpha=0.95, intraclass correlation coefficient=0.88). In patients with CADASIL, CADASIL Patient-Reported Outcome scores correlated with the modified Rankin Scale, Starkstein Apathy Scale, Hospital Anxiety and Depression scale, Working Memory Index, and trail making test times. In patients with other cSVDs, CADASIL Patient-Reported Outcome correlated only with Hospital Anxiety and Depression scale and Starkstein Apathy Scale.

CONCLUSIONS

The CADASIL Patient-Reported Outcome may be an innovative instrument for measuring patient-reported outcomes in future cSVD trials. Full validation was obtained for its use in patients with CADASIL, but further improvement is needed for its application in other cSVDs.

Genetic testing in dementia

There is growing public awareness and concern regarding dementia risk. In addition, genetic testing is increasingly accessible and is at the point of being integrated into routine clinical practice. As a result, there is a pressing need for treating clinicians to have the appropriate knowledge base to request and consent for diagnostic genetic testing in cognitive clinics. We outline our approach to genetic testing in patients with Alzheimer's disease, frontotemporal dementia, dementia with Lewy bodies and vascular cognitive impairment. We discuss when to consider testing, the consenting process, and the interpretation and communication of genetic test results.

Clinical and neuroradiological spectrum of biallelic variants in NOTCH3

BACKGROUND

NOTCH3 encodes a transmembrane receptor critical for vascular smooth muscle cell function. NOTCH3 variants are the leading cause of hereditary cerebral small vessel disease (SVD). While monoallelic cysteine-involving missense variants in NOTCH3 are well-studied in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), patients with biallelic variants in NOTCH3 are extremely rare and not well characterised.

METHODS

In this study, we present clinical and genetic data from 25 patients with biallelic NOTCH3 variants and conduct a literature review of another 25 cases (50 patients in total). Brain magnetic resonance imaging (MRI) were analysed by expert neuroradiologists to better understand the phenotype associated with biallelic NOTCH3 variants.

FINDINGS

Our systematic analyses verified distinct genotype-phenotype correlations for the two types of biallelic variants in NOTCH3. Biallelic loss-of-function variants (26 patients) lead to a neurodevelopmental disorder characterised by spasticity, childhood-onset stroke, and periatrial white matter volume loss resembling periventricular leukomalacia. Conversely, patients with biallelic cysteine-involving missense variants (24 patients) fall within CADASIL spectrum phenotype with early adulthood onset stroke, dementia, and deep white matter lesions without significant volume loss. White matter lesion volume is comparable between patients with biallelic cysteine-involving missense variants and individuals with CADASIL. Notably, monoallelic carriers of loss-of-function variants are predominantly asymptomatic, with only a few cases reporting nonspecific headaches.

INTERPRETATION

We propose a NOTCH3-SVD classification depending on dosage and variant type. This study not only expands our knowledge of biallelic NOTCH3 variants but also provides valuable insight into the underlying mechanisms of the disease, contributing to a more comprehensive understanding of NOTCH3-related SVD.

FUNDING

The Wellcome Trust, the MRC.

Identifying the Pathogenic Variants in Heart Genes in Vietnamese Sudden Unexplained Death Victims by Next-Generation Sequencing

In forensics, one-third of sudden deaths remain unexplained after a forensic autopsy. A majority of these sudden unexplained deaths (SUDs) are considered to be caused by inherited cardiovascular diseases. In this study, we investigated 40 young SUD cases (<40 years), with non-diagnostic structural cardiac abnormalities, using Targeted NGS (next-generation sequencing) for 167 genes previously associated with inherited cardiomyopathies and channelopathies. Fifteen cases identified 17 variants on related genes including the following: AKAP9, CSRP3, GSN, HTRA1, KCNA5, LAMA4, MYBPC3, MYH6, MYLK, RYR2, SCN5A, SCN10A, SLC4A3, TNNI3, TNNI3K, and TNNT2. Of these, eight variants were novel, and nine variants were reported in the ClinVar database. Five were determined to be pathogenic and four were not evaluated. The novel and unevaluated variants were predicted by using in silico tools, which revealed that four novel variants (c.5187_5188dup, p.Arg1730llefsTer4 in the AKAP9 gene; c.1454A>T, p.Lys485Met in the MYH6 gene; c.2535+1G>A in the SLC4A3 gene; and c.10498G>T, p.Asp3500Tyr in the RYR2 gene) were pathogenic and three variants (c.292C>G, p.Arg98Gly in the TNNI3 gene; c.683C>A, p.Pro228His in the KCN5A gene; and c.2275G>A, p.Glu759Lys in the MYBPC3 gene) still need to be further verified experimentally. The results of our study contributed to the general understanding of the causes of SUDs. They provided a scientific basis for screening the risk of sudden death in family members of victims. They also suggested that the Targeted NGS method may be used to identify the pathogenic variants in SUD victims.

Phenotypes Associated with NOTCH3 Cysteine-Sparing Mutations in Patients with Clinical Suspicion of CADASIL: A Systematic Review

CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) is caused by NOTCH3 mutations affecting the number of cysteines. The pathogenic role of cysteine-sparing NOTCH3 mutations with typical clinical CADASIL syndrome is still debated. This review aimed to characterize NOTCH3 cysteine-sparing mutations in patients with clinical suspicion of CADASIL. Articles on NOTCH3 cysteine-sparing mutations with clinical suspicion of CADASIL were reviewed. Clinical and radiological cerebral phenotypes data were extracted and characterized across regions and compared with phenotypes of typical CADASIL patients. We screened 298 NOTCH3 cysteine-sparing mutation individuals from 20 publications, and mutations in exon 3 were the most frequently reported (21.46%). Gait impairment (76.47%), cognitive impairment (67.47%), and stroke (62.37%) were the three most common clinical phenotypes; the most frequent radiological cerebral phenotypes were lacunes (74.29%) and cerebral microbleeds (72.73%). Compared with CADASIL patients, cognitive impairment and cerebral microbleed frequencies were significantly higher in patients with NOTCH3 cysteine-sparing mutations, while the white matter hyperintensities in anterior temporal polar and external capsule were rarely observed. Compared with Western patients, radiological phenotypes were more common than clinical phenotypes in cysteine-sparing Asian patients. More than half of cysteine-sparing patients had positive granular osmiophilic material deposits. NOTCH3 cysteine-sparing mutations in patients with clinical suspicion of CADASIL mainly manifested with gait and cognitive impairment but rare white matter hyperintensities in anterior temporal pole and external capsule. Further studies are warranted to pay attention to atypical NOTCH3 variants, which could guide specific diagnosis and help unravel underlying mechanisms.

Vascular cognitive impairment: Advances in clinical research and management

ABSTRACT

Vascular cognitive impairment (VCI) encompasses a wide spectrum of cognitive disorders, ranging from mild cognitive impairment to vascular dementia. Its diagnosis relies on thorough clinical evaluations and neuroimaging. VCI predominately arises from vascular risk factors (VRFs) and cerebrovascular disease, either independently or in conjunction with neurodegeneration. Growing evidence underscores the prevalence of VRFs, highlighting their potential for early prediction of cognitive impairment and dementia in later life. The precise mechanisms linking vascular pathologies to cognitive deficits remain elusive. Chronic cerebrovascular pathology is the most common neuropathological feature of VCI, often interacting synergistically with neurodegenerative processes. Current research efforts are focused on developing and validating reliable biomarkers to unravel the etiology of vascular brain changes in VCI. The collaborative integration of these biomarkers into clinical practice, alongside routine incorporation into neuropathological assessments, presents a promising strategy for predicting and stratifying VCI. The cornerstone of VCI prevention remains the control of VRFs, which includes multi-domain lifestyle modifications. Identifying appropriate pharmacological approaches is also of paramount importance. In this review, we synthesize recent advancements in the field of VCI, including its definition, determinants of vascular risk, pathophysiology, neuroimaging and fluid-correlated biomarkers, predictive methodologies, and current intervention strategies. Increasingly evident is the notion that more rigorous research for VCI, which arises from a complex interplay of physiological events, is still needed to pave the way for better clinical outcomes and enhanced quality of life for affected individuals.

Multiorgan manifestations of COL4A1 and COL4A2 variants and proposal for a clinical management protocol

COL4A1/2 variants are associated with highly variable multiorgan manifestations. Depicting the whole clinical spectrum of COL4A1/2-related manifestations is challenging, and there is no consensus on management and preventative strategies. Based on a systematic review of current evidence on COL4A1/2-related disease, we developed a clinical questionnaire that we administered to 43 individuals from 23 distinct families carrying pathogenic variants. In this cohort, we extended ophthalmological and cardiological examinations to asymptomatic individuals and those with only limited or mild, often nonspecific, clinical signs commonly occurring in the general population (i.e., oligosymptomatic). The most frequent clinical findings emerging from both the literature review and the questionnaire included stroke (203/685, 29.6%), seizures or epilepsy (199/685, 29.0%), intellectual disability or developmental delay (168/685, 24.5%), porencephaly/schizencephaly (168/685, 24.5%), motor impairment (162/685, 23.6%), cataract (124/685, 18.1%), hematuria (63/685, 9.2%), and retinal arterial tortuosity (58/685, 8.5%). In oligosymptomatic and asymptomatic carriers, ophthalmological investigations detected retinal vascular tortuosity (5/13, 38.5%), dysgenesis of the anterior segment (4/13, 30.8%), and cataract (2/13, 15.4%), while cardiological investigations were unremarkable except for mild ascending aortic ectasia in 1/8 (12.5%). Our multimodal approach confirms highly variable penetrance and expressivity in COL4A1/2-related conditions, even at the intrafamilial level with neurological involvement being the most frequent and severe finding in both children and adults. We propose a protocol for prevention and management based on individualized risk estimation and periodic multiorgan evaluations.

Proteogenomics in cerebrospinal fluid and plasma reveals new biological fingerprint of cerebral small vessel disease

Cerebral small vessel disease (cSVD) is a leading cause of stroke and dementia with no specific mechanism-based treatment. We used Mendelian randomization to combine a unique cerebrospinal fluid (CSF) and plasma pQTL resource with the latest European-ancestry GWAS of MRI-markers of cSVD (white matter hyperintensities, perivascular spaces). We describe a new biological fingerprint of 49 protein-cSVD associations, predominantly in the CSF. We implemented a multipronged follow-up, across fluids, platforms, and ancestries (Europeans and East-Asian), including testing associations of direct plasma protein measurements with MRI-cSVD. We highlight 16 proteins robustly associated in both CSF and plasma, with 24/4 proteins identified in CSF/plasma only. cSVD-proteins were enriched in extracellular matrix and immune response pathways, and in genes enriched in microglia and specific microglial states (integration with single-nucleus RNA sequencing). Immune-related proteins were associated with MRI-cSVD already at age twenty. Half of cSVD-proteins were associated with stroke, dementia, or both, and seven cSVD-proteins are targets for known drugs (used for other indications in directions compatible with beneficial therapeutic effects. This first cSVD proteogenomic signature opens new avenues for biomarker and therapeutic developments.

Neglected Mendelian causes of stroke in adult Chinese patients who had an ischaemic stroke or transient ischaemic attack

BACKGROUND AND PURPOSE

Multiple factors play important roles in the occurrence and prognosis of stroke. However, the roles of monogenic variants in all-cause ischaemic stroke have not been systematically investigated. We aim to identify underdiagnosed monogenic stroke in an adult ischaemic stroke/transient ischaemic attack (TIA) cohort (the Third China National Stroke Registry, CNSR-III).

METHODS

Targeted next-generation sequencing for 181 genes associated with stroke was conducted on DNA samples from 10 428 patients recruited through CNSR-III. The genetic and clinical data from electronic health records (EHRs) were reviewed for completion of the diagnostic process. We assessed the percentages of individuals with pathogenic or likely pathogenic (P/LP) variants, and the diagnostic yield of pathogenic variants in known monogenic disease genes with associated phenotypes.

RESULTS

In total, 1953 individuals harboured at least one P/LP variant out of 10 428 patients. Then, 792 (7.6%) individuals (comprising 759 individuals harbouring one P/LP variant in one gene, 29 individuals harbouring two or more P/LP variants in different genes and 4 individuals with two P/LP variants in ABCC6) were predicted to be at risk for one or more monogenic diseases based on the inheritance pattern. Finally, 230 of 792 individuals manifested a clinical phenotype in the EHR data to support the diagnosis of stroke with a monogenic cause. The most diagnosed Mendelian cause of stroke in the cohort was cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. There were no relationships between age or family history and the incidence of first symptomatic monogenic stroke in patients.

CONCLUSION

The rate of monogenic cause of stroke was 2.2% after reviewing the clinical phenotype. Possible reasons that Mendelian causes of stroke may be missed in adult patients who had an ischaemic stroke/TIA include a late onset of stroke symptoms, combination with common vascular risks and the absence of a prominent family history.

Pathophysiology of cerebral small vessel disease: a journey through recent discoveries

Cerebral small vessel disease (cSVD) encompasses a heterogeneous group of age-related small vessel pathologies that affect multiple regions. Disease manifestations range from lesions incidentally detected on neuroimaging (white matter hyperintensities, small deep infarcts, microbleeds, or enlarged perivascular spaces) to severe disability and cognitive impairment. cSVD accounts for approximately 25% of ischemic strokes and the vast majority of spontaneous intracerebral hemorrhage and is also the most important vascular contributor to dementia. Despite its high prevalence and potentially long therapeutic window, there are still no mechanism-based treatments. Here, we provide an overview of the recent advances in this field. We summarize recent data highlighting the remarkable continuum between monogenic and multifactorial cSVDs involving NOTCH3, HTRA1, and COL4A1/A2 genes. Taking a vessel-centric view, we discuss possible cause-and-effect relationships between risk factors, structural and functional vessel changes, and disease manifestations, underscoring some major knowledge gaps. Although endothelial dysfunction is rightly considered a central feature of cSVD, the contributions of smooth muscle cells, pericytes, and other perivascular cells warrant continued investigation.

Virtual hospital and artificial intelligence: a first step towards the application of an innovative health system for the care of rare cerebrovascular diseases

The development of virtual care options, including virtual hospital platforms, is rapidly changing the healthcare, mostly in the pandemic period, due to difficulties in in-person consultations. For this purpose, in 2020, a neurological Virtual Hospital (NOVHO) pilot study has been implemented, in order to experiment a multidisciplinary second opinion evaluation system for neurological diseases. Cerebrovascular diseases represent a preponderant part of neurological disorders. However, more than 30% of strokes remain of undetermined source, and rare CVD (rCVD) are often misdiagnosed. The lack of data on phenotype and clinical course of rCVD patients makes the diagnosis and the development of therapies challenging. Since the diagnosis and care of rCVDs require adequate expertise and instrumental tools, their management is mostly allocated to a few experienced hospitals, making difficult equity in access to care. Therefore, strategies for virtual consultations are increasingly applied with some advantage for patient management also in peripheral areas. Moreover, health data are becoming increasingly complex and require new technologies to be managed. The use of Artificial Intelligence is beginning to be applied to the healthcare system and together with the Internet of Things will enable the creation of virtual models with predictive abilities, bringing healthcare one step closer to personalized medicine. Herein, we will report on the preliminary results of the NOVHO project and present the methodology of a new project aimed at developing an innovative multidisciplinary and multicentre virtual care model, specific for rCVD (NOVHO-rCVD), which combines the virtual hospital approach and the deep-learning machine system.

Prevalence, clinical characteristics, and risk factors of intracerebral haemorrhage in CADASIL: a case series and systematic review

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common monogenic form of stroke and is characterised by early onset stroke and dementia. Most strokes are lacunar ischaemic strokes, but intracerebral haemorrhage (ICH) has also been reported, although there are limited published data on its frequency and characteristics.

METHODS

A retrospective review of a prospectively recruited CADASIL register from the British National Referral clinic was performed to identify acute ICH cases and their characteristics. In addition, a systematic review of ICH in CADASIL was performed. MEDLINE (Pubmed), Embase, and Web of Science were searched for articles published from inception until 31/05/2023.

RESULTS

Ten cases of ICH were identified from the National clinic register of 516 symptomatic patients, giving an estimated point prevalence of 1.9%. An additional 119 cases were identified from the systematic review, comprising 129 cases and 142 ICH events in total. Including all identified cases, the mean age at onset of ICH was 56.6 ± 15.7 (SD) years, and 74 (57.4%) were male. ICH was the first manifestation of the disease in 32 patients (38.1%), and ICH recurrence occurred in 16 (12.4%). Most ICHs were subcortical, with the thalamus, 58 (40.8%), and basal ganglia, 34 (23.9%), being the commonest sites. Anticoagulation, but not antiplatelet agents, was associated with an increased risk of ICH (20.0% vs. 1.9%, p = 0.006).

CONCLUSIONS

ICH is a relatively rare manifestation of CADASIL, occurring in about 2% of symptomatic cases. Most of the haemorrhages occurred in the subcortical regions.

Stroke genetics and how it Informs novel drug discovery

INTRODUCTION

Stroke is one of the main causes of death and disability worldwide. Nevertheless, despite the global burden of this disease, our understanding is limited and there is still a lack of highly efficient etiopathology-based treatment. It is partly due to the complexity and heterogenicity of the disease. It is estimated that around one-third of ischemic stroke is heritable, emphasizing the importance of genetic factors identification and targeting for therapeutic purposes.

AREAS COVERED

In this review, the authors provide an overview of the current knowledge of stroke genetics and its value in diagnostics, personalized treatment, and prognostication.

EXPERT OPINION

As the scale of genetic testing increases and the cost decreases, integration of genetic data into clinical practice is inevitable, enabling assessing individual risk, providing personalized prognostic models and identifying new therapeutic targets and biomarkers. Although expanding stroke genetics data provides different diagnostics and treatment perspectives, there are some limitations and challenges to face. One of them is the threat of health disparities as non-European populations are underrepresented in genetic datasets. Finally, a deeper understanding of underlying mechanisms of potential targets is still lacking, delaying the application of novel therapies into routine clinical practice.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) with multiple different onset forms of frequent recurrent attacks: A case report and literature review

INTRODUCTION

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is one kind of monogenic hereditary small-vessel disease in the brain caused by mutations in the NOTCH3 gene. However, it is rare for CADASIL to recur with different clinical manifestations in 1 patient, and some atypical clinical manifestations can easily lead to misdiagnosis by clinical physicians.

CASE CONCERN

A 34-year-old male presented with transient speech disorder accompanied by weakness in the left side of the body for 1 day in June 2020. Magnetic resonance imaging showed acute ischemic infarction in right centrum semiovale, along with multiple abnormal white matter hyperintensities in the brain. Genetic sequencing identified a heterozygous mutation in the NOTCH3 gene. The patient experienced recurrent episodes in 2021 and 2023, with varying clinical symptoms including visual blurring, abnormal limb sensation, and sudden cognitive dysfunction.

DIAGNOSIS

The diagnoses of CADASIL is based on clinical manifestations, imaging results, and genetic reports.

INTERVISION AND OUTCOMES

The patient was received symptomatic treatment including antiplatelet aggregation therapy, lipid regulation, and plaque stabilization, resulting in improved symptoms.

OUTCOMES

During the course of the disease, after medication treatment and rehabilitation exercise, the patient clinical symptoms have significantly improved. Currently, the patient is closely following up and regularly undergoing relevant examinations.

LESSONS

In this rare case, we found that CADASIL can recur multiple times in a patient with different clinical symptoms, which can easily lead to clinical misdiagnosis. Clinicians should consider the possibility of CADASIL in young patients with sudden typical neurological dysfunction.

European stroke organisation (ESO) guideline on cerebral small vessel disease, part 2, lacunar ischaemic stroke

A quarter of ischaemic strokes are lacunar subtype, typically neurologically mild, usually resulting from intrinsic cerebral small vessel pathology, with risk factor profiles and outcome rates differing from other stroke subtypes. This European Stroke Organisation (ESO) guideline provides evidence-based recommendations to assist with clinical decisions about management of lacunar ischaemic stroke to prevent adverse clinical outcomes. The guideline was developed according to ESO standard operating procedures and Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. We addressed acute treatment (including progressive lacunar stroke) and secondary prevention in lacunar ischaemic stroke, and prioritised the interventions of thrombolysis, antiplatelet drugs, blood pressure lowering, lipid lowering, lifestyle, and other interventions and their potential effects on the clinical outcomes recurrent stroke, dependency, major adverse cardiovascular events, death, cognitive decline, mobility, gait, or mood disorders. We systematically reviewed the literature, assessed the evidence and where feasible formulated evidence-based recommendations, and expert concensus statements. We found little direct evidence, mostly of low quality. We recommend that patients with suspected acute lacunar ischaemic stroke receive intravenous alteplase, antiplatelet drugs and avoid blood pressure lowering according to current acute ischaemic stroke guidelines. For secondary prevention, we recommend single antiplatelet treatment long-term, blood pressure control, and lipid lowering according to current guidelines. We recommend smoking cessation, regular exercise, other healthy lifestyle modifications, and avoid obesity for general health benefits. We cannot make any recommendation concerning progressive stroke or other drugs. Large randomised controlled trials with clinically important endpoints, including cognitive endpoints, are a priority for lacunar ischaemic stroke.

Research Advancements on the Correlation Between Spontaneous Intracerebral Hemorrhage of Different Etiologies and Imaging Markers of Cerebral Small Vessel Disease

Objective

The purpose of this review is to identify the correlation between ICH and CSVD imaging markers under SMASH-U classification by searching and analyzing a large number of literatures in recent years, laying a theoretical foundation for future clinical research. At the same time, by collecting clinical data to evaluate patient prognosis, analyzing whether there are differences or supplements between clinical trial conclusions and previous theories, and ultimately guiding clinical diagnosis and treatment through the analysis of imaging biomarkers.

Methods

In this review, by searching CNKI, Web of Science, PubMed, FMRS and other databases, the use of "spontaneous intracerebral hemorrhage", "hypertensive hemorrhagic cerebral small vessel disease", "cerebral small vessel disease imaging", "Based cerebral small vessel diseases", "SMASH the -u classification" and their Chinese equivalents for the main search term. We focused on reading and analyzing hundreds of relevant literatures in the last decade from August 2011 to April 2020, and also included some earlier literatures with conceptual data sources. After screening and ranking the degree of relevance to this study, sixty of them were cited for analysis and elaboration.

Results

In patients with ICH, the number of cerebral microbleeds in lobes, basal ganglia, and the deep brain is positively correlated with ICH volume and independently correlated with neurological functional outcomes; white matter hyperintensity severity is positively correlated with ICH recurrence risk; multiple lacunar infarction independently predict the risk of ICH; severe brain atrophy is an independent risk factor for a poor prognosis in the long term in patients diagnosed with ICH; and the number of enlarged perivascular spaces is correlated with ICH recurrence. However, small subcortical infarct and ICH are the subject of few studies. Higher CSVD scores are independently associated with functional outcomes at 90 days in patients diagnosed with ICH.

Clinical and neuroimaging review of monogenic cerebral small vessel disease from the prenatal to adolescent developmental stage

Cerebral small vessel disease (cSVD) refers to a group of pathological processes with various etiologies affecting the small vessels of the brain. Most cases are sporadic, with age-related and hypertension-related sSVD and cerebral amyloid angiopathy being the most prevalent forms. Monogenic cSVD accounts for up to 5% of causes of stroke. Several causative genes have been identified. Sporadic cSVD has been widely studied whereas monogenic cSVD is still poorly characterized and understood. The majority of cases of both the sporadic and monogenic types, including cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), typically have their onset in adulthood. Types of cSVD with infantile and childhood onset are rare, and their diagnosis is often challenging. The present review discusses the clinical and neuroimaging findings of monogenic cSVD from the prenatal to adolescent period of development. Early diagnosis is crucial to enabling timely interventions and family counseling.

Progress to Clarify How NOTCH3 Mutations Lead to CADASIL, a Hereditary Cerebral Small Vessel Disease

Notch signaling is conserved in C. elegans, Drosophila, and mammals. Among the four NOTCH genes in humans, NOTCH1, NOTCH2, and NOTCH3 are known to cause monogenic hereditary disorders. Most NOTCH-related disorders are congenital and caused by a gain or loss of Notch signaling activity. In contrast, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) caused by NOTCH3 is adult-onset and considered to be caused by accumulation of the mutant NOTCH3 extracellular domain (N3ECD) and, possibly, by an impairment in Notch signaling. Pathophysiological processes following mutant N3ECD accumulation have been intensively investigated; however, the process leading to N3ECD accumulation and its association with canonical NOTCH3 signaling remain unknown. We reviewed the progress in clarifying the pathophysiological process involving mutant NOTCH3.

CADASIL: A NOTCH3-associated cerebral small vessel disease

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common hereditary cerebral small vessel disease (CSVD), pathologically characterized by a non-atherosclerotic and non-amyloid diffuse angiopathy primarily involving small to medium-sized penetrating arteries and leptomeningeal arteries. In 1996, mutation in the notch receptor 3 gene (NOTCH3) was identified as the cause of CADASIL. However, since that time other genetic CSVDs have been described, including the HtrA serine peptidase 1 gene-associated CSVD and the cathepsin A gene-associated CSVD, that clinically mimic the original phenotype. Though NOTCH3-associated CSVD is now a well-recognized hereditary disorder and the number of studies investigating this disease is increasing, the role of NOTCH3 in the pathogenesis of CADASIL remains elusive.

AIM OF REVIEW

This review aims to provide insights into the pathogenesis and the diagnosis of hereditary CSVDs, as well as personalized therapy, predictive approach, and targeted prevention. In this review, we summarize the current progress in CADASIL, including the clinical, neuroimaging, pathological, genetic, diagnostic, and therapeutic aspects, as well as differential diagnosis, in which the role of NOTCH3 mutations is highlighted.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In this review, CADASIL is revisited as a NOTCH3-associated CSVD along with other hereditary CSVDs.

Lysosomal storage diseases

Lysosomal storage disorders (LSDs) are a group of inherited metabolic diseases caused by dysfunction of the lysosomal system, with subsequent progressive accumulation of macromolecules, activation of inflammatory response, and cell death. Neurologic damage is almost always present, and it is usually degenerative. White matter (WM) involvement may be primary or secondary. Diseases with primary WM involvement are leukodystrophies, demyelinating (Krabbe disease and metachromatic leukodystrophy), and hypomyelinating leukodystrophies (free sialic acid storage disease, fucosidosis, and mucolipidosis type IV). LSDs with secondary WM involvement are classified as leukoencephalopathies and include gangliosidosis, mucopolysaccharidosis (MPS), ceroid neuronal lipofuscinosis, multiple sulfatase deficiency, alpha-mannosidosis, Pompe disease, and Fabry disease. Neurologic manifestations may overlap among LSDs and include developmental delays, motor, cognitive and speech impairments, seizures, visual failure, ataxia, and extrapyramidal signs. Most of LSDs are typically present in early or late infancy, but juvenile and adult forms also exist and are associated with predominantly neuropsychiatric and behavioral symptoms. The outcome of these disorders is generally poor and specific treatments (enzyme replacement therapy, hematopoietic stem cell transplantation, or gene therapy) are only available in a small number of them.

Cerebral Small Vessel Disease, Hypertension, and Vascular Contributions to Cognitive Impairment and Dementia

Hypertension-associated cerebral small vessel disease is a common finding in older people. Strongly associated with age and hypertension, small vessel disease is found at autopsy in over 50% of people aged ≥65 years, with a spectrum of clinical manifestations. It is the main cause of lacunar stroke and a major source of vascular contributions to cognitive impairment and dementia. The brain areas affected are subcortical and periventricular white matter and deep gray nuclei. Neuropathological sequelae are diffuse white matter lesions (seen as white matter hyperintensities on T2-weighted magnetic resonance imaging), small ischemic foci (lacunes or microinfarcts), and less commonly, subcortical microhemorrhages. The most common form of cerebral small vessel disease is concentric, fibrotic thickening of small penetrating arteries (up to 300 microns outer diameter) termed arteriolosclerosis. Less common forms are small artery atheroma and lipohyalinosis (the lesions described by C. Miller Fisher adjacent to lacunes). Other microvascular lesions that are not reviewed here include cerebral amyloid angiopathy and venous collagenosis. Here, we review the epidemiology, neuropathology, clinical management, genetics, preclinical models, and pathogenesis of hypertensive small vessel disease. Knowledge gaps include initiating factors, molecular pathogenesis, relationships between arterial pathology and tissue damage, possible reversibility, pharmacological targets, and molecular biomarkers. Progress is anticipated from multicell transcriptomic and proteomic profiling, novel experimental models and further target-finding and interventional clinical studies.

Monogenic causes of cerebral small vessel disease and stroke

Cerebral small vessel disease (cSVDs) account for 25% of stroke and are a frequent cause of cognitive or motor disability in adults. In a small number of patients, cSVDs result from monogenic diseases, the most frequent being cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). An early disease onset, a suggestive family history, and a low vascular risk profile contrasting with a high load of cSVD imaging markers represent red flags that must trigger molecular screening. To date, a dozen of genes is involved in Mendelian cSVDs, most of them are responsible for autosomal dominant conditions of variable penetrance. Some of these mendelian cSVDs (CADASIL, HTRA1-related cSVD, pontine autosomal dominant microangiopathy and leukoencephalopathy (PADMAL), cathepsin-A related arteriopathy with strokes and leukoencephalopathy (CARASAL), and cSVD related to LAMB1 mutations) are causing ischemic stroke. Others (COL4A1/COL4A2-related angiopathy and hereditary cerebral amyloid angiopathy) preferentially lead to intracerebral hemorrhages. The clinical features of different Mendelian cSVDs can overlap. Therefore, the current approach is based on simultaneous screening of all genes involved in these conditions through a panel-targeted sequencing gene or exome sequencing. Nevertheless, a pathogenic variant is identified in less than 15% of patients with a suspected genetic cerebrovascular disease, suggesting that many additional genes remain to be identified.

Modifiable vascular risk factors contribute to stroke in 1080 NOTCH3 R544C carriers in Taiwan Biobank

BACKGROUND AND AIM

Previous studies have suggested cardiovascular risk factors increase the risk of not only common sporadic stroke but also of stroke in patients with monogenic stroke disorders including CADASIL. We investigated the effects of the NOTCH3 Arg544Cys (R544C) variant and associated vascular risk factors on stroke in the Taiwanese population.

METHODS

This study was conducted using data from the Taiwan Biobank, consisting of at least 130,000 Han Chinese participants. The genotype was derived from customized genome-wide arrays for 650,000 to 750,000 single-nucleotide polymorphisms (SNPs). Individuals with NOTCH3 R544C were subsequently matched with noncarriers based on the propensity score at a 1:10 ratio by demographic and cardiovascular risk factors. The odds ratio (OR) for stroke or other phenotypes in NOTCH3 R544C carriers and matched noncarriers was then calculated. Univariate and multivariate regression analyses were performed on cardiovascular risk factors in NOTCH3 R544C carriers with and without stroke. The polygenic risk score (PRS) model, adopted from the UK Biobank, was then applied to evaluate the role of NOTCH3 R544C in stroke.

RESULTS

From the 114,282 participants with both genotype and questionnaire results, 1080 (0.95%) harbored the pathogenic NOTCH3 R544C variant. When compared to the matched controls (n = 10,800), the carriers presented with a history of stroke (OR: 2.52, 95% confidence interval (CI) (1.45, 4.37)), dementia (OR: 30.1, 95% CI (3.13, 289.43)), and sibling history of stroke (OR: 2.48, 95% CI (1.85, 3.34)) phenotypes. The risk of stroke increased with every 10-year increase in age (p = 0.006, Cochran-Mantel-Haenszel test). Among NOTCH3 R544C carriers, 16 (1.3%) of the 1080 carriers with a stroke history were older, male, and more likely to have hypertension, diabetes, dyslipidemia, and a family history of stroke. In the stepwise multivariate analysis, hypertension (OR: 11.28, 95% CI (3.54, 43.3)) and diabetes mellitus (OR: 4.10, 95% CI (1.31, 12.4)) were independently associated with stroke. Harboring the NOTCH3 R544C variant in the Taiwan Biobank is comparable with a 6.74 standard deviations increase in individual's polygenic risk score for stroke.

CONCLUSION

While the NOTCH3 R544C variant alone increased the risk of stroke, modifiable vascular risk factors also played a role in the occurrence of stroke in Taiwanese community-dwelling individuals carrying the NOTCH3 variant.

A novel human iPSC model of COL4A1/A2 small vessel disease unveils a key pathogenic role of matrix metalloproteinases

Cerebral small vessel disease (SVD) affects the small vessels in the brain and is a leading cause of stroke and dementia. Emerging evidence supports a role of the extracellular matrix (ECM), at the interface between blood and brain, in the progression of SVD pathology, but this remains poorly characterized. To address ECM role in SVD, we developed a co-culture model of mural and endothelial cells using human induced pluripotent stem cells from patients with COL4A1/A2 SVD-related mutations. This model revealed that these mutations induce apoptosis, migration defects, ECM remodeling, and transcriptome changes in mural cells. Importantly, these mural cell defects exert a detrimental effect on endothelial cell tight junctions through paracrine actions. COL4A1/A2 models also express high levels of matrix metalloproteinases (MMPs), and inhibiting MMP activity partially rescues the ECM abnormalities and mural cell phenotypic changes. These data provide a basis for targeting MMP as a therapeutic opportunity in SVD.

'Raisin bread sign' feature of pontine autosomal dominant microangiopathy and leukoencephalopathy

Pontine autosomal dominant microangiopathy and leukoencephalopathy is one of hereditary cerebral small vessel diseases caused by pathogenic variants in COL4A1 3'UTR and characterized by multiple small infarctions in the pons. We attempted to establish radiological features of this disease. We performed whole exome sequencing and Sanger sequencing in one family with undetermined familial small vessel disease, followed by clinicoradiological assessment and a postmortem examination. We subsequently investigated clinicoradiological features of patients in a juvenile cerebral vessel disease cohort and searched for radiological features similar to those found in the aforementioned family. Sanger sequencing was performed in selected cohort patients in order to detect variants in the same gene. An identical variant in the COL4A1 3'UTR was observed in two patients with familial small vessel disease and the two selected patients, thereby confirming the pontine autosomal dominant microangiopathy and leukoencephalopathy diagnosis. Furthermore, postmortem examination showed that the distribution of thickened media tunica and hyalinized vessels was different from that in lacunar infarctions. The appearance of characteristic multiple oval small infarctions in the pons, which resemble raisin bread, enable us to make a diagnosis of pontine autosomal dominant microangiopathy and leukoencephalopathy. This feature, for which we coined the name 'raisin bread sign', was also correlated to the pathological changes.

Deep learning based on susceptibility-weighted MR sequence for detecting cerebral microbleeds and classifying cerebral small vessel disease

BACKGROUND

Cerebral microbleeds (CMBs) serve as neuroimaging biomarkers to assess risk of intracerebral hemorrhage and diagnose cerebral small vessel disease (CSVD). Therefore, detecting CMBs can evaluate the risk of intracerebral hemorrhage and use its presence to support CSVD classification, both are conducive to optimizing CSVD management. This study aimed to develop and test a deep learning (DL) model based on susceptibility-weighted MR sequence (SWS) to detect CMBs and classify CSVD to assist neurologists in optimizing CSVD management. Patients with arteriolosclerosis (aSVD), cerebral amyloid angiopathy (CAA), and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) treated at three centers were enrolled between January 2017 and May 2022 in this retrospective study. The SWSs of patients from two centers were used as the development set, and the SWSs of patients from the remaining center were used as the external test set. The DL model contains a Mask R-CNN for detecting CMBs and a multi-instance learning (MIL) network for classifying CSVD. The metrics for model performance included intersection over union (IoU), Dice score, recall, confusion matrices, receiver operating characteristic curve (ROC) analysis, accuracy, precision, and F1-score.

RESULTS

A total of 364 SWS were recruited, including 336 in the development set and 28 in the external test set. IoU for the model was 0.523 ± 0.319, Dice score 0.627 ± 0.296, and recall 0.706 ± 0.365 for CMBs detection in the external test set. For CSVD classification, the model achieved a weighted-average AUC of 0.908 (95% CI 0.895-0.921), accuracy of 0.819 (95% CI 0.768-0.870), weighted-average precision of 0.864 (95% CI 0.831-0.897), and weighted-average F1-score of 0.829 (95% CI 0.782-0.876) in the external set, outperforming the performance of the neurologist group.

CONCLUSION

The DL model based on SWS can detect CMBs and classify CSVD, thereby assisting neurologists in optimizing CSVD management.

Clinical considerations in early-onset cerebral amyloid angiopathy

Cerebral amyloid angiopathy (CAA) is an important cerebral small vessel disease associated with brain haemorrhage and cognitive change. The commonest form, sporadic amyloid-β CAA, usually affects people in mid- to later life. However, early-onset forms, though uncommon, are increasingly recognized and may result from genetic or iatrogenic causes that warrant specific and focused investigation and management. In this review, we firstly describe the causes of early-onset CAA, including monogenic causes of amyloid-β CAA (APP missense mutations and copy number variants; mutations of PSEN1 and PSEN2) and non-amyloid-β CAA (associated with ITM2B, CST3, GSN, PRNP and TTR mutations), and other unusual sporadic and acquired causes including the newly-recognized iatrogenic subtype. We then provide a structured approach for investigating early-onset CAA, and highlight important management considerations. Improving awareness of these unusual forms of CAA amongst healthcare professionals is essential for facilitating their prompt diagnosis, and an understanding of their underlying pathophysiology may have implications for more common, late-onset, forms of the disease.

Management of Inherited CNS Small Vessel Diseases: The CADASIL Example: A Scientific Statement From the American Heart Association

Lacunar infarcts and vascular dementia are important phenotypic characteristics of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, the most common inherited cerebral small vessel disease. Individuals with the disease show variability in the nature and onset of symptoms and rates of progression, which are only partially explained by differences in pathogenic mutations in the NOTCH3 gene. Recognizing the disease early in its course and securing a molecular diagnosis are important clinical goals, despite the lack of proven disease-modifying treatments. The purposes of this scientific statement are to review the clinical, genetic, and imaging aspects of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, contrasting it with other inherited small vessel diseases, and to provide key prevention, management, and therapeutic considerations with the intent of reducing practice variability and encouraging production of high-quality evidence to support future treatment recommendations.

Case report: Recurrent pontine stroke and leukoencephalopathy in a patient with de novo mutation in COL4A1

This report presents a case of pontine autosomal dominant microangiopathy with leukoencephalopathy (PADMAL) in a 35 year-old male patient. The patient exhibited a consistent history of recurrent ischemic strokes, concentrated primarily in the pons region, accompanied by concurrent manifestations of leukoencephalopathy and microbleeds. Genetic evaluation revealed a heterozygous missense mutation consistent with c.3431C>G, p. Thr1144Arg substitution within exon 40 of the COL4A1 gene. This mutation was also identified in the patient's mother, affirming an autosomal dominant inheritance model. Our findings serve as testament to the potential role of mutation in the exon 40 of COL4A1 in the pathogenesis and progression of PADMAL, contributing to ongoing efforts aimed at better understanding the genetic basis of this debilitating disorder.

Consensus statement for the management of incidentally found brain white matter hyperintensities in general medical practice

INTRODUCTION

There is a paradigm shift in our understanding of white matter hyperintensities (WMH) found on brain imaging. They were once thought to be a normal phenomenon of ageing and, therefore, warranted no further investigation. However, evidence now suggests these lesions are markers of poor brain and cardiovascular health, portending an increased risk of stroke, cognitive decline, depression and death. Nevertheless, no specific guidelines exist for the management of incidentally found WMH for general medical practitioners and other clinicians ordering brain magnetic resonance imaging scans for diverse clinical indications. Informed by a literature review and expert opinion gleaned from stroke neurologists, medical and imaging specialists, and general practitioners, we present our consensus statement to guide the management of incidentally found WMH in adults.

MAIN RECOMMENDATIONS

When incidental WMH are found on brain imaging: Perform a detailed history and examination to screen for neurological events. Investigate for potential undiagnosed or undertreated cardiovascular risk factors, especially hypertension and diabetes mellitus. Commence intensive and individualised cardiovascular risk management when risk factors are uncovered. Treat underlying risk factors via accepted guidelines but note that antiplatelet and anticoagulant medications should not be prescribed for incidental WMH in the absence of an alternative indication.

CHANGES TO MANAGEMENT AS A RESULT OF THIS CONSENSUS STATEMENT

A brain health opportunity. We consider the discovery of incidental WMH on brain imaging to represent an opportunity to investigate for common cardiovascular risk factors and to optimise brain health. This can be commenced and monitored by the general practitioner or physician without delay in waiting for an outpatient neurology review.

Effects of intensive blood pressure control on cognitive function in patients with cerebral small vessel disease

OBJECTIVE

This study aimed to investigate the effects of intensive blood pressure control on cognitive function in elderly patients with cerebral small vessel disease (CSVD).

METHODS

From May 2020 to June 2022, 140 outpatients and inpatients with CSVD and hypertension in the Department of Neurology of Beijing Shijingshan Hospital were selected. They were randomly divided into the standard and intensive blood pressure control groups, and the dosage of antihypertensive drugs was adjusted to reduce the blood pressure to the target level. The patients were followed up for 2 years. The medical records or data at "enrollment" and "2-year follow-up" were analyzed and evaluated. The Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were used to evaluate cognitive function. Cranial magnetic resonance imaging was performed to evaluate lacunar infarctions (LIs) and white matter hyperintensity (WMH). Multiple linear regression was used to analyze the correlation between MMSE scores and blood pressure, WMH, and LIs.

RESULTS

(1) The MMSE and MoCA scores in the standard group were significantly lower than those at enrollment. The WMH score in the standard group was significantly higher than that at enrollment. (2) After the 2-year follow-up, the 24-h systolic blood pressure (SBP), 24-h diastolic blood pressure (DBP), daytime mean SBP, daytime mean DBP, and nighttime mean SBP in the two groups significantly decreased, which had significant statistical significance (P < 0.05). (3) The correlation between blood pressure and MMSE score was analyzed using multiple linear regression analysis. The WMH score, LIs, 24-h SBP, and 24-h DBP were independently correlated with MMSE scores.

CONCLUSION

In elderly patients with hypertension, a decrease in SBP to 126 mmHg, compared with 134 mmHg, can delay cognitive impairment as well as reduce LIs and cerebral WMH lesions in patients with CSVD.

Redefining cerebral palsies as a diverse group of neurodevelopmental disorders with genetic aetiology

Cerebral palsy is a clinical descriptor covering a diverse group of permanent, non-degenerative disorders of motor function. Around one-third of cases have now been shown to have an underlying genetic aetiology, with the genetic landscape overlapping with those of neurodevelopmental disorders including intellectual disability, epilepsy, speech and language disorders and autism. Here we review the current state of genomic testing in cerebral palsy, highlighting the benefits for personalized medicine and the imperative to consider aetiology during clinical diagnosis. With earlier clinical diagnosis now possible, we emphasize the opportunity for comprehensive and early genomic testing as a crucial component of the routine diagnostic work-up in people with cerebral palsy.

Lifelong cerebrovascular disease burden among CADASIL patients: analysis from a global health research network

Introduction

Data reporting on patients with Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) within the United States population is limited. We sought to evaluate the overt cerebrovascular disease burden among patients with CADASIL.

Methods

Harmonized electronic medical records were extracted from the TriNetX global health research network. CADASIL patients were identified using diagnostic codes and those with/without history of documented stroke sub-types (ischemic stroke [IS], intracerebral hemorrhage [ICH], subarachnoid hemorrhage [SAH] and transient ischemic attack [TIA]) were compared. Adjusted odds ratios (OR) and 95% confidence intervals (CI) of stroke incidence and mortality associated with sex were computed.

Results

Between September 2018 and April 2020, 914 CADASIL patients were identified (median [IQR] age: 60 [50-69], 61.3% females); of whom 596 (65.2%) had documented cerebrovascular events (i.e., CADASIL-Stroke patients). Among CADASIL-Stroke patients, 89.4% experienced an IS, co-existing with TIAs in 27.7% and hemorrhagic strokes in 6.2%; initial stroke events occurred ≤65 years of age in 71% of patients. CADASIL-Stroke patients (vs. CADASIL-non-Stroke) had higher cardiovascular and neurological (migraines, cognitive impairment, epilepsy/seizures, mood disorders) burden. In age- and comorbidity-adjusted models, males had higher associated risk of stroke onset (OR: 1.37, CI: 1.01-1.86). Mortality risk was higher for males (OR: 2.72, CI: 1.53-4.84).

Discussion

Early screening and targeted treatment strategies are warranted to help CADASIL patients with symptom management and risk mitigation.

Advances in Management of the Stroke Etiology One-Percenters

PURPOSE OF REVIEW

Uncommon causes of stroke merit specific attention; when clinicians have less common etiologies of stoke in mind, the diagnosis may come more easily. This is key, as optimal management will in many cases differs significantly from "standard" care.

RECENT FINDINGS

Randomized controlled trials (RCT) on the best medical therapy in the treatment of cervical artery dissection (CeAD) have demonstrated low rates of ischemia with both antiplatelet and vitamin K antagonism. RCT evidence supports the use of anticoagulation with vitamin K antagonism in "high-risk" patients with antiphospholipid antibody syndrome (APLAS), and there is new evidence supporting the utilization of direct oral anticoagulation in malignancy-associated thrombosis. Migraine with aura has been more conclusively linked not only with increased risk of ischemic and hemorrhagic stroke, but also with cardiovascular mortality. Recent literature has surprisingly not provided support the utilization of L-arginine in the treatment of patients with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS); however, there is evidence at this time that support use of enzyme replacement in patients with Fabry disease. Additional triggers for reversible cerebral vasoconstriction syndrome (RCVS) have been identified, such as capsaicin. Imaging of cerebral blood vessel walls utilizing contrast-enhanced MRA is an emerging modality that may ultimately prove to be very useful in the evaluation of patients with uncommon causes of stroke. A plethora of associations between cerebrovascular disease and COVID-19 have been described. Where pertinent, authors provide additional tips and guidance. Less commonly encountered conditions with updates in diagnosis, and management along with clinical tips are reviewed.

Clinical and epidemiological profiles from a case series of 26 Brazilian CADASIL patients

BACKGROUND

 Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a genetic cause of ischemic stroke and the most common form of non-atherosclerotic stroke. Despite being the most prevalent vascular hereditary disease, clinical data regarding the Brazilian population are scarce. Considering that the Brazilian population has one of the most heterogeneous genetic constitutions in the world, knowledge about genetic and epidemiological profiles is mandatory. The present study aimed to elucidate the epidemiological and clinical features of CADASIL in Brazil.

METHODS

 We performed a case series study comprising 6 rehabilitation hospitals in Brazil and reported the clinical and epidemiological data from the medical records of patients admitted from 2002 to 2019 with genetic confirmation.

RESULTS

 We enrolled 26 (16 female) patients in whom mutations in exons 4 and 19 were the most common. The mean age at the onset of the disease was of 45 years. Ischemic stroke was the first cardinal symptom in 19 patients. Cognitive impairment, dementia, and psychiatric manifestations were detected in 17, 6, and 16 patients respectively. In total, 8 patients had recurrent migraines, with aura in 6 (75%) of them. White matter hyperintensities in the temporal lobe and the external capsule were found in 20 (91%) and 15 patients (68%) respectively. The median Fazekas score was of 2. Lacunar infarcts, microbleeds, and larger hemorrhages were observed in 18 (82%), 9, and 2 patients respectively.

CONCLUSION

 The present is the most extensive series of Brazilian CADASIL patients published to date, and we have reported the first case of microbleeds in the spinal cord of a CADASIL patient. Most of our clinical and epidemiological data are in accordance with European cohorts, except for microbleeds and hemorrhagic strokes, for which rates fall in between those of European and Asian cohorts.

Mutations in ARHGEF15 cause autosomal dominant hereditary cerebral small vessel disease and osteoporotic fracture

Cerebral small vessel disease (CSVD) is a prominent cause of ischemic and hemorrhagic stroke and a leading cause of vascular dementia, affecting small penetrating vessels of the brain. Despite current advances in genetic susceptibility studies, challenges remain in defining the causative genes and the underlying pathophysiological mechanisms. Here, we reported that the ARHGEF15 gene was a causal gene linked to autosomal dominant inherited CSVD. We identified one heterozygous nonsynonymous mutation of the ARHGEF15 gene that cosegregated completely in two families with CSVD, and a heterozygous nonsynonymous mutation and a stop-gain mutation in two individuals with sporadic CSVD, respectively. Intriguingly, clinical imaging and pathological findings displayed severe osteoporosis and even osteoporotic fractures in all the ARHGEF15 mutation carriers. In vitro experiments indicated that ARHGEF15 mutations resulted in RhoA/ROCK2 inactivation-induced F-actin cytoskeleton disorganization in vascular smooth muscle cells and endothelial cells and osteoblast dysfunction by inhibiting the Wnt/β-catenin signaling pathway in osteoblast cells. Furthermore, Arhgef15-e(V368M)1 transgenic mice developed CSVD-like pathological and behavioral phenotypes, accompanied by severe osteoporosis. Taken together, our findings provide strong evidence that loss-of-function mutations of the ARHGEF15 gene cause CSVD accompanied by osteoporotic fracture.

Genetic Causes of Cerebral Small Vessel Diseases: A Practical Guide for Neurologists

Cerebral small vessel disease (CSVD) includes various entities affecting the brain and, often, systemic small arteries, arterioles, venules, and capillaries. The underlying causes of CSVD are different, and some of them are genetic. Monogenic CSVDs are responsible for 1%-5% of all strokes and for several other disturbances. Despite many genes being involved, the phenotypes of monogenic CSVD partly overlap. Given that the genetic testing for different diseases can be challenging and time-consuming, the practicing neurologist should be adequately informed of the genetic background of CSVD and should be able to select patients to undergo genetic assessment and the genes to be analyzed. The purpose of this review was to summarize clinical, neurologic and non-neurologic, and neuroimaging features of monogenic CSVD and to provide a flowchart to be used in clinical practice to guide neurologists in this field. The proposed flowchart and the relative tables can be applied to 3 different settings, depending on the presentation: (1) ischemic stroke and/or transient ischemic attack, (2) cerebral hemorrhage, and (3) other neurologic, non-neurologic, and/or neuroimaging features of monogenic CSVD, in the absence of stroke syndromes because of infarction or hemorrhage.

Diagnostic Evaluation of Stroke Etiology

OBJECTIVE

Precise therapies require precise diagnoses. This article provides an evidence-based approach to confirming the diagnosis of ischemic stroke, characterizing comorbidities that provide insights into the pathophysiologic mechanisms of stroke, and identifying targets for treatment to optimize the prevention of recurrent stroke.

LATEST DEVELOPMENTS

Identifying the presence of patent foramen ovale, intermittent atrial fibrillation, and unstable plaque is now routinely included in an increasingly nuanced workup in patients with stroke, even as ongoing trials seek to clarify the best approaches for treating these and other comorbidities. Multicenter trials have demonstrated the therapeutic utility of patent foramen ovale closure in select patients younger than age 60 years. Insertable cardiac monitors detect atrial fibrillation lasting more than 30 seconds in about one in ten patients monitored for 12 months following a stroke. MRI of carotid plaque can detect unstable plaque at risk of being a source of cerebral embolism.

ESSENTIAL POINTS

To optimize the prevention of recurrent stroke, it is important to consider pathologies of intracranial and extracranial blood vessels and of cardiac structure and rhythm as well as other inherited or systemic causes of stroke. Some aspects of the stroke workup should be done routinely, while other components will depend on the clinical circumstances and preliminary testing results.

Antiplatelet use and CADASIL: a retrospective observational analysis

OBJECTIVES

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is hallmarked by age-dependent accumulation of microangiopathy with antiplatelet medications commonly used for stroke prevention though without known therapeutic benefit. Our objective was to identify whether antiplatelet therapy impacted the incidence of acute ischemic stroke (AIS) or intracerebral hemorrhage (ICH) in those with reported CADASIL.

MATERIALS AND METHODS

Owing to the rarity of the disease, we performed a retrospective study of anonymized data from the international TriNetX Research Network (Oct 2015 through January 2021). Individuals had an ICD-10 code (I67.850) for CADASIL. The primary outcome was incidence of validated ICD-10 codes for AIS (I63) and ICH (I61) linked with unique hospital admission encounters. The primary exposure was use of an antiplatelet medication for at least 1 month prior to the primary outcome. Age-adjusted logistic regression was used for likelihood ratios.

RESULTS

We identified 455 individuals: 36% female, 40 (8.8%) antiplatelet exposed. Those with antiplatelet use were older (antiplatelet: 61±12 years vs. unexposed: 57±14 years, p = 0.034) with similar rates of AIS [antiplatelet: 23%(9/40) vs. unexposed: 14%(60/415); p=0.18] and ICH [antiplatelet: 3%(1/40) vs. unexposed: 5%(19/415); p = 0.54) and without significant impact on age-adjusted AIS likelihood (OR 1.62, 95%CI 0.73-3.60, p=0.23). Sample size precluded ICH regression analyses.

CONCLUSIONS

Our data suggests that antiplatelet use did not significantly impact incidence of AIS or ICH within a group of individuals with suspected CADASIL This study highlights the need for further understanding of the pathophysiology of CADASIL to lead to disease modifying treatments.

Management of Coronary Artery Disease in CADASIL Patients: Review of Current Literature

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common heritable form of vascular dementia in adults. It is well-established that CADASIL results in neurocognitive dysfunction and mood disturbance. There is also cumulative evidence that CADASIL patients are more susceptible to ischemic heart disease. The aim of this study is to review the current literature regarding the incidence of coronary artery disease in CADASIL patients with a focus on the various management options and the clinical challenges associated with each of these treatment strategies. We conducted a literature search using Cochrane, MEDLINE, and EMBASE for papers that reported the occurrence of coronary artery disease in patients with CADASIL. We supplemented the search with a manual search in Google Scholar. Only case reports, case series, and original articles were included. The search resulted in six reports indicating the association between coronary artery disease and CADASIL and its management. Evidence suggests that extracranial manifestations of CADASIL may include coronary artery disease, presenting as a more extensive burden of disease in younger patients. Surgical and percutaneous revascularization strategies are feasible, but the incidence of peri-procedural stroke remains significant and should be weighed against the potential benefit derived from either of these strategies. A multidisciplinary approach to therapy, with perspectives from neurologists, cardiologists, and cardiac surgeons, is needed to provide the appropriate treatment to the CADASIL patient with severe coronary artery disease. Future studies should be directed toward the development of targeted therapies that may help with the early detection and prevention of disease progress in these patients.

Heterozygous Pathogenic and Likely Pathogenic Symptomatic HTRA1 Variant Carriers in Cerebral Small Vessel Disease

High temperature requirement serine peptidase A1 (HTRA1) related cerebral small vessel disease (CSVD) includes both symptomatic heterozygous HTRA1 variant carrier and cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) patients. Presently, most reported symptomatic heterozygous HTRA1 variant carrier cases are sporadic family reports with a lack of specific characteristics. Additionally, the molecular mechanism of heterozygous HTRA1 gene variants is unclear. We conducted this review to collect symptomatic carriers of heterozygous HTRA1 gene variants reported as of 2022, analyzed all pathogenicity according to American College of Medical Genetics and Genomics (ACMG) variant classification, and summarized the cases with pathogenic and likely pathogenic HTRA1 variants gender characteristics, age of onset, geographical distribution, initial symptoms, clinical manifestations, imaging signs, HTRA1 gene variant information and to speculate its underlying pathogenic mechanisms. In this review, we summarized the following characteristics of pathogenic and likely pathogenic symptomatic HTRA1 variant carriers: to date, the majority of reported symptomatic HTRA1 carriers are in European and Asian countries, particularly in China which was found to have the highest number of reported cases. The age of first onset is mostly concentrated in the fourth and fifth decades. The heterozygous HTRA1 gene variants were mostly missense variants. The two variant sites, 166-182 aa and 274-302 aa, were the most concentrated. Clinicians need to pay attention to de novo data and functional data, which may affect the pathogenicity analysis. The decrease in HtrA1 protease activity is currently the most important explanation for the genetic pathogenesis.

Stroke-like episodes in adult mitochondrial disease

Stroke-like episode is a paroxysmal neurological manifestation which affects a specific group of patients with mitochondrial disease. Focal-onset seizures, encephalopathy, and visual disturbances are prominent findings associated with stroke-like episodes, with a predilection for the posterior cerebral cortex. The most common cause of stroke-like episodes is the m.3243A>G variant in MT-TL1 gene followed by recessive POLG variants. This chapter aims to review the definition of stroke-like episode and delineate the clinical phenomenology, neuroimaging and EEG findings typically seen in patients. In addition, several lines of evidence supporting neuronal hyper-excitability as the key mechanism of stroke-like episodes are discussed. The management of stroke-like episodes should focus on aggressive seizure management and treatment for concomitant complications such as intestinal pseudo-obstruction. There is no robust evidence to prove the efficacy of l-arginine for both acute and prophylactic settings. Progressive brain atrophy and dementia are the sequalae of recurrent stroke-like episode, and the underlying genotype in part predicts prognosis.

Motoric Cognitive Risk Syndrome Among Chinese Older Adults with White Matter Lesions: A Cross-Sectional Observational Study

Brain aging is characterized by the declines in motor and cognitive features. The present study is to detect motor cognitive risk syndrome (MCRS) in older adults with white matter lesions (WML). 134 WML aged patients were recruited and diagnosed with the criteria for MCRS. Numerous cognitive function tests and walking tests were performed. The frequency of MCRS is 28.35%. Verbal fluency test, Mini-Mental State Examination, and dual-task walking speed were independent risk factor of MCRS. These findings indicated that MCRS was common in WML seniors. MCRS was associated with the pathologies of WML in older adults.

Clinical features and pathogenicity assessment in patients with HTRA1-autosomal dominant disease

BACKGROUND

Heterozygous mutations in HTRA1 were recently found to cause autosomal dominant cerebral small vessel disease (CSVD), and it was named HTRA1-autosomal dominant disease (AD-HTRA1) in the consensus recommendations of the European Academy of Neurology. This study aimed to investigate the clinical features of a mutation in HTRA1 and the effect of HTRA1 mutation on white matter hyperintensity (WMH).

METHODS

A proband's brain magnetic resonance imaging (MRI) showed multiple lacunar infarctions and multiple WMH in the lateral ventricle, external capsule, frontal lobe and corpus callosum. The proband and family members were tested for CSVD-related genes by next-generation sequencing and the clinical data of the patients were collected. The published literature on AD-HTRA1 was collected, and the clinical characteristics and pathogenicity of the patients were summarized. Combined Annotation Dependent Depletion (CADD) is a tool for scoring the deleteriousness of single-nucleotide variants and insertion/deletion variants in the human genome. The relationship between the degree of WMH and the pathogenicity of the mutation was further analyzed.

RESULT

It was found that the proband and her family members had a heterozygous missense mutation of c.854C > T (p.P285L) in the 4 exon of HTRA1 gene. A retrospective analysis of 5 families with c.854C > T mutation found that the patients had an early age of onset, cognitive impairment was more common, and alopecia and spondylosis could be combined at the same time. By univariate analysis, the severity of WMH was found to be significantly associated with the mutated CADD score (p < 0.05, Spearman's rho = 0.266).

CONCLUSION

The clinical manifestations of AD-HTRA1 with mutation site c.854C > T (p.P285L) are similar to CARASIL, and brain MRI are mainly moderate or severe WMH and lacunar infarction (LI). WMH are affected by mutation sites. Therefore, our pathogenicity score for mutations can predict the severity of WMH.

Exome-based gene panel analysis in a cohort of acute juvenile ischemic stroke patients:relevance of NOTCH3 and GLA variants

BACKGROUND

Genetic variants are considered to have a crucial impact on the occurrence of ischemic stroke. In clinical routine, the diagnostic value of next-generation sequencing (NGS) in the medical clarification of acute juvenile stroke has not been investigated so far.

MATERIAL AND METHODS

We analyzed an exome-based gene panel of 349 genes in 172 clinically well-characterized patients with magnetic resonance imaging (MRI)-proven, juvenile (age ≤ 55 years), ischemic stroke admitted to a single comprehensive stroke center.

RESULTS

Monogenetic diseases causing ischemic stroke were observed in five patients (2.9%): In three patients with lacunar stroke (1.7%), we identified pathogenic variants in NOTCH3 causing cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Hence, CADASIL was identified at a frequency of 12.5% in the lacunar stroke subgroup. Further, in two male patients (1.2%) suffering from lacunar and cardioembolic stroke, pathogenic variants in GLA causing Fabry's disease were present. Additionally, genetic variants in monogenetic diseases lacking impact on stroke occurrence, variants of unclear significance (VUS) in monogenetic diseases, and (cardiovascular-) risk genes in ischemic stroke were observed in a total of 15 patients (15.7%).

CONCLUSION

Genetic screening for Fabry's disease in cardioembolic and lacunar stroke as well as CADASIL in lacunar stroke might be beneficial in routine medical work-up of acute juvenile ischemic stroke.