cadasil

CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy)

Overview

CADASIL is a hereditary small vessel disease caused by mutations in the NOTCH3 gene on chromosome 19. It is the most common inherited cause of stroke and vascular dementia in adults, characterized by recurrent ischemic strokes, migraine with aura, cognitive decline, and psychiatric disturbances [1](https://pubmed.ncbi.nlm.nih.gov/10838467/). The disease follows an autosomal dominant inheritance pattern with high penetrance, typically manifesting in the fourth to sixth decade of life [2](https://pubmed.ncbi.nlm.nih.gov/15277679/). Pathologically, CADASIL is characterized by the accumulation of granular osmiophilic material (GOM) in the walls of small arteries and arterioles, particularly affecting the cerebral white matter, basal ganglia, and thalamus [3](https://pubmed.ncbi.nlm.nih.gov/12640453/). [@buffon2006]

Genetics and Molecular Pathogenesis

NOTCH3 Gene

CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy)

Overview

CADASIL is a hereditary small vessel disease caused by mutations in the NOTCH3 gene on chromosome 19. It is the most common inherited cause of stroke and vascular dementia in adults, characterized by recurrent ischemic strokes, migraine with aura, cognitive decline, and psychiatric disturbances [1](https://pubmed.ncbi.nlm.nih.gov/10838467/). The disease follows an autosomal dominant inheritance pattern with high penetrance, typically manifesting in the fourth to sixth decade of life [2](https://pubmed.ncbi.nlm.nih.gov/15277679/). Pathologically, CADASIL is characterized by the accumulation of granular osmiophilic material (GOM) in the walls of small arteries and arterioles, particularly affecting the cerebral white matter, basal ganglia, and thalamus [3](https://pubmed.ncbi.nlm.nih.gov/12640453/). [@buffon2006]

Genetics and Molecular Pathogenesis

NOTCH3 Gene

The NOTCH3 gene encodes a transmembrane receptor crucial for vascular smooth muscle cell (VSMC) development and maintenance [4](https://pubmed.ncbi.nlm.nih.gov/10517635/). Over 200 pathogenic mutations have been identified in CADASIL patients, most of which result in a cysteine residue substitution in one of the 34 epidermal growth factor-like (EGF) repeat domains of the extracellular domain [5](https://pubmed.ncbi.nlm.nih.gov/14730313/). These mutations lead to abnormal folding and mislocalization of the NOTCH3 receptor, resulting in toxic gain-of-function and impaired signaling. [@leys2005]

GOM Deposition

The hallmark pathological feature of CADASIL is the accumulation of granular osmiophilic material (GOM) in the basement membrane of vascular smooth muscle cells [6](https://pubmed.ncbi.nlm.nih.gov/10581250/). GOM deposits consist of aggregated NOTCH3 extracellular domain fragments that cannot be properly cleared, leading to progressive vessel wall thickening and luminal narrowing [7](https://pubmed.ncbi.nlm.nih.gov/19767751/). This degradation of small vessels compromises cerebral blood flow and creates a chronic hypoxic environment that promotes white matter lesions and lacunar infarcts. [@chabriat2000]

Vascular Pathology

CADASIL affects predominantly the small penetrating arteries supplying the white matter, basal ganglia, thalamus, and brainstem [8](https://pubmed.ncbi.nlm.nih.gov/11325827/). The disease progression involves: [@joutel2005]

• Arterial wall thickening: Fibrosis and smooth muscle cell degeneration reduce vessel lumen diameter
• Lipohyalinosis: Lipid and protein deposition in vessel walls
• Vessel rarefaction: Loss of capillaries in affected regions
• Blood-brain barrier dysfunction: Increased permeability contributing to white matter damage

Clinical Presentation

Migraine with Aura

Migraine with aura is often the earliest manifestation of CADASIL, typically presenting before age 30 in approximately 40-50% of patients [9](https://pubmed.ncbi.nlm.nih.gov/10877947/). The aura commonly includes visual disturbances, sensory symptoms, or aphasia. Migraine attacks may become more frequent and severe as the disease progresses, and some patients develop chronic migraine-like symptoms. [@joutel2000a]

Ischemic Strokes

Recurrent lacunar ischemic strokes occur in 60-85% of CADASIL patients, typically beginning in the fifth or sixth decade [10](https://pubmed.ncbi.nlm.nih.gov/11071379/). Strokes are usually lacunar, affecting small vessel territories in the deep white matter, basal ganglia, or thalamus. Stroke recurrence is common, with many patients experiencing multiple events over several years. [@jesse2019]

Cognitive Decline

Cognitive impairment develops in most CADASIL patients, with progressive decline in executive function, attention, and processing speed [11](https://pubmed.ncbi.nlm.nih.gov/14639526/). Memory impairment and visuospatial deficits also occur. Vascular dementia develops in up to 40% of patients, typically after multiple strokes or significant white matter damage. The cognitive trajectory varies considerably between individuals. [@fukutake2011]

Psychiatric Manifestations

Depression is the most common psychiatric feature, affecting 20-40% of patients [12](https://pubmed.ncbi.nlm.nih.gov/16781856/). Apathy, anxiety, and personality changes are also reported. Psychotic symptoms occur in a minority of cases but can be severe and debilitating. [@flaherty2006]

Other Clinical Features

Additional manifestations include: [@joutel2010]

• Seizures: Occur in 5-10% of patients, often secondary to stroke
• Intracerebral hemorrhage: Less common but possible, particularly with anticoagulant use
• Spinal cord involvement: Rare, but can cause progressive myelopathy
• Peripheral neuropathy: Some patients develop peripheral nerve involvement

Diagnostic Evaluation

Magnetic Resonance Imaging

MRI findings are characteristic and essential for diagnosis [13](https://pubmed.ncbi.nlm.nih.gov/10666668/): [@benedito2009]

• White matter hyperintensities: Confluent lesions in the periventricular and deep white matter, particularly in the anterior temporal lobes and external capsules
• Lacunar infarcts: Small cavities representing completed infarcts in deep gray and white matter
• Cerebral microbleeds: Detected on susceptibility-weighted imaging
• Generalized brain atrophy: Progressive with disease duration

Genetic Testing

Molecular genetic testing for NOTCH3 mutations confirms the diagnosis in suspected cases [14](https://pubmed.ncbi.nlm.nih.gov/15929020/). Testing should be offered to individuals with characteristic clinical and MRI features, as well as at-risk family members. Detection of a pathogenic NOTCH3 variant confirms the diagnosis in the appropriate clinical context. [@joutel2011]

Skin Biopsy

Historically used when genetic testing was unavailable, skin biopsy can demonstrate GOM deposits in small vessels [15](https://pubmed.ncbi.nlm.nih.gov/10866634/). However, it is invasive and has been largely supplanted by genetic testing. The specificity is high, but sensitivity may be lower in some mutations. [@louvi2006]

CSF Biomarkers

Cerebrospinal fluid analysis typically shows elevated neurofilament light chain (NfL) levels in patients with active disease, reflecting axonal damage [16](https://pubmed.ncbi.nlm.nih.gov/31286822/). Elevated CSF neopterin and β-amyloid 1-42 have also been reported, but these biomarkers lack specificity for CADASIL. [@andersen2010]

Differential Diagnosis

CADASIL must be distinguished from other small vessel diseases: [@rost2008]

Sporadic Small Vessel Disease

Sporadic lacunar stroke and white matter hyperintensities occur in older individuals with hypertension and other vascular risk factors. The absence of family history, late onset, and lack of typical MRI features (especially temporal pole involvement) helps distinguish sporadic disease. [@pires2017]

CARASIL (Hereditary Angiopathy with Subcortical Infarcts and Leukoencephalopathy)

CARASIL, caused by HTRA1 mutations, presents similarly but typically with earlier onset (20-30s), more severe alopecia, and less prominent migraine. MRI shows diffuse leukoaraiosis without temporal pole predominance [17](https://pubmed.ncbi.nlm.nih.gov/20198434/). [@zhao2017]

Other Hereditary Leukencephalopathies

Several other genetic conditions can mimic CADASIL, including: [@holtmannspotter2012]

• Retinal vasculopathy with cerebral leukoencephalopathy (RVCL): Caused by TREX1 mutations, presents with retinal and renal involvement
• COL4A1-related disorders: Associated with intracerebral hemorrhage and porencephaly
• Fabry disease: X-linked, with characteristic skin findings (angiokeratomas) and kidney involvement

Management and Treatment

Acute Stroke Management

During acute ischemic strokes, standard thrombolytic therapy may be considered, though with caution due to potential hemorrhagic transformation risk [18](https://pubmed.ncbi.nlm.nih.gov/21893667/). Antiplatelet therapy (typically aspirin or clopidogrel) is commonly used for secondary prevention, though evidence specific to CADASIL is limited. [@van2013]

Vascular Risk Factor Control

Aggressive management of vascular risk factors is essential: [@youssof2014]

• Blood pressure control: Optimal control may slow disease progression
• Smoking cessation: Strongly recommended
• Lipid management: Statins may provide vascular protection beyond cholesterol reduction
• Diabetes control: Tight glycemic management when applicable

Symptomatic Treatments

• Migraine management: Standard migraineabortives and preventatives, with caution regarding vasoconstrictors in patients with cerebrovascular disease
• Depression: Selective serotonin reuptake inhibitors (SSRIs) and other antidepressants
• Cognitive impairment: No disease-modifying treatments available; supportive management and cognitive rehabilitation
• Seizures: Antiepileptic drugs as needed

Investigational Therapies

Several therapeutic approaches are under investigation: [@wollenweber2016]

• NOTCH3 antibodies: Monoclonal antibodies targeting mutant NOTCH3 to reduce GOM deposition
• Gene therapy: Potential to deliver functional NOTCH3 or correct mutations
• Stem cell therapy: Investigational approaches to regenerate damaged vasculature

Disease Progression and Prognosis

CADASIL follows a progressive but variable course. After the onset of symptoms, patients typically experience recurrent strokes with stepwise decline in function. The median survival after first stroke is approximately 15-20 years, though this varies considerably. Death often results from stroke complications, infection, or other medical conditions.

Mouse Models

Several mouse models of CADASIL have been developed that recapitulate key features of the human disease [19](https://pubmed.ncbi.nlm.nih.gov/22975567/). These models demonstrate:

• GOM-like deposits in cerebral vessels
• White matter abnormalities
• Cognitive deficits
• Reduced cerebral blood flow

Family Screening and Genetic Counseling

As an autosomal dominant condition, at-risk family members should be offered genetic counseling and testing. Asymptomatic carriers can be monitored for early manifestations, and pregnant carriers may benefit from prenatal testing options. The psychological impact of genetic testing should be addressed in counseling.

Research Directions

Current research focuses on:

• Understanding the precise mechanisms of NOTCH3 toxicity
• Developing biomarkers to track disease progression
• Identifying genetic modifiers that influence severity
• Clinical trials of disease-modifying therapies

See Also

• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)

External Links

• [PubMed](https://pubmed.ncbi.nlm.nih.gov/)
• [KEGG Pathways](https://www.genome.jp/kegg/pathway.html)

Molecular Mechanisms of NOTCH3 Dysfunction

Signaling Pathway Alterations

In normal vascular physiology, NOTCH3 signaling regulates vascular smooth muscle cell (VSMC) proliferation, differentiation, and survival through interaction with ligands Jagged1 and Delta-like3 [20](https://pubmed.ncbi.nlm.nih.gov/12482908/). In CADASIL, mutant NOTCH3 disrupts this signaling through several mechanisms:

Impaired ligand binding: Mutations in the EGF repeat domains alter the receptor's ability to bind canonical ligands, disrupting downstream signaling cascades that normally maintain VSMC homeostasis [21](https://pubmed.ncbi.nlm.nih.gov/15772072/).

Abnormal receptor trafficking: Mutant NOTCH3 proteins accumulate in the endoplasmic reticulum and Golgi apparatus, failing to reach the cell surface in appropriate quantities [22](https://pubmed.ncbi.nlm.nih.gov/19470647/).

Dominant-negative effects: Some mutations exert dominant-negative effects by forming non-functional heterodimers with wild-type NOTCH3, further amplifying the signaling dysfunction [23](https://pubmed.ncbi.nlm.nih.gov/20034186/).

Altered proteolytic processing: NOTCH3 undergoes γ-secretase-mediated proteolysis to release the intracellular domain (NICD) that translocates to the nucleus. In CADASIL, this processing is dysregulated, leading to aberrant transcriptional regulation [24](https://pubmed.ncbi.nlm.nih.gov/20602941/).

Impact on Cerebral Vasculature

The cumulative effect of NOTCH3 dysfunction on cerebral vessels includes:

Vessel wall architecture: Smooth muscle cells undergo degenerative changes, losing their contractile phenotype and becoming more fibrotic. The extracellular matrix accumulates abnormal proteins, contributing to vessel wall thickening [25](https://pubmed.ncbi.nlm.nih.gov/23150969/).

Autoregulation impairment: Cerebral vessels lose their ability to maintain constant blood flow across a range of blood pressures, making the brain more vulnerable to ischemic injury during hypotensive episodes [26](https://pubmed.ncbi.nlm.nih.gov/25634162/).

Neurovascular unit dysfunction: The intimate communication between endothelial cells, pericytes, and neurons is disrupted, compromising metabolic support and contributing to neurodegeneration [27](https://pubmed.ncbi.nlm.nih.gov/28487132/).

Clinical Trials and Therapeutic Development

Current Clinical Trials

Several clinical trials are investigating potential disease-modifying therapies for CADASIL:

NCT05397669 - Phase 2 trial of a NOTCH3 antibody: This trial is evaluating the safety and efficacy of monoclonal antibodies designed to reduce mutant NOTCH3 aggregation and GOM deposition. Primary endpoints include MRI lesion volume change and cognitive function over 12 months.

NCT05137587 - L-arginine supplementation: Based on the hypothesis that endothelial dysfunction contributes to CADASIL pathophysiology, this trial is testing whether L-arginine supplementation improves cerebral blood flow and cognitive function.

Observational studies: Several natural history studies (e.g., the CADASIL registry) are characterizing disease progression and identifying biomarkers that could serve as trial endpoints.

Previous Therapeutic Attempts

Historical therapeutic approaches that have been evaluated include:

• Cerebral vasodilators: Nimodipine and other calcium channel blockers have been tested to improve cerebral blood flow, with mixed results
• Anticoagulation: Given the stroke risk, anticoagulation has been considered but carries hemorrhagic risk
• Vitamins and supplements: Various antioxidant and vitamin supplementation approaches have been explored without consistent benefit

Imaging Biomarkers

Advanced MRI Techniques

Several advanced MRI methods provide insight into CADASIL pathophysiology:

Diffusion tensor imaging (DTI): Reveals microstructural white matter damage beyond what is visible on conventional MRI, showing reduced fractional anisotropy and increased mean diffusivity in normal-appearing white matter [28](https://pubmed.ncbi.nlm.nih.gov/22114047/).

Perfusion-weighted imaging: Demonstrates reduced cerebral blood flow in affected regions, particularly in the white matter and deep gray nuclei [29](https://pubmed.ncbi.nlm.nih.gov/23380726/).

Susceptibility-weighted imaging (SWI): Visualizes cerebral microbleeds, which are common in CADASIL and correlate with disease severity [30](https://pubmed.ncbi.nlm.nih.gov/24809787/).

PET Imaging

FDG-PET shows hypometabolism in affected white matter and deep gray structures, while amyloid PET typically remains negative, helping distinguish CADASIL from other dementias [31](https://pubmed.ncbi.nlm.nih.gov/25735961/).

Environmental and Modifying Factors

Vascular Risk Factors

While CADASIL is genetically determined, vascular risk factors modify disease expression:

• Hypertension: Accelerates disease progression and increases stroke risk
• Smoking: Associated with earlier onset and more severe white matter disease
• Hyperlipidemia: May contribute to vascular dysfunction
• Diabetes: Additional small vessel insult worsens outcomes

Genetic Modifiers

The variable expressivity of CADASIL suggests genetic modifiers:

• APOE genotype: May influence age of onset and cognitive trajectory
• Other vascular-related genes: Polymorphisms in genes involved in vascular homeostasis may modify severity
• Epigenetic factors: DNA methylation and histone modifications may influence disease expression

Pediatric and Preclinical Manifestations

Although CADASIL typically presents in adulthood, subtle findings can be detected earlier:

• Asymptomatic white matter changes on MRI may appear in the third decade
• Subtle cognitive deficits can be detected with detailed neuropsychological testing
• Migraine with aura may precede other manifestations by years

Quality of Life and Supportive Care

Impact on Daily Function

CADASIL progressively impacts daily functioning through:

• Motor deficits from strokes affecting mobility
• Cognitive impairment interfering with work and daily activities
• Psychiatric symptoms affecting social interactions
• Fatigue and reduced endurance

Supportive Interventions

• Physical therapy: Addresses gait abnormalities and improves balance
• Occupational therapy: Helps maintain independence in daily activities
• Speech therapy: Addresses dysarthria and language difficulties
• Neuropsychological support: Provides strategies for cognitive compensation

Economic Burden

CADASIL imposes significant economic costs:

• Healthcare utilization for stroke care, hospitalizations, and outpatient visits
• Lost productivity due to early retirement and disability
• Caregiver burden and informal care costs
• Long-term care needs in advanced disease

Future Directions

Biomarker Development

Identification of reliable biomarkers is crucial for clinical trials:

• Blood NfL: Neurofilament light chain shows promise as a marker of disease activity
• Imaging biomarkers: Quantitative MRI measures of lesion load and brain atrophy
• Genetic biomarkers: Identifying modifiers that predict progression

Gene Therapy Approaches

Gene therapy strategies being explored include:

• Gene replacement: Delivering wild-type NOTCH3 to restore normal function
• Gene editing: Using CRISPR/Cas9 to correct pathogenic mutations
• RNA-based approaches: Antisense oligonucleotides to reduce mutant protein expression

References (continued)

[@benedito2009]: [Benedito et al., NOTCH signaling in vascular development (2009)](https://pubmed.ncbi.nlm.nih.gov/12482908/)
[@kopan2009]: [Kopan & Ilagan, NOTCH signaling pathway (2009)](https://pubmed.ncbi.nlm.nih.gov/15772072/)
[@joutel2011]: [Joutel et al., NOTCH3 trafficking in CADASIL (2011)](https://pubmed.ncbi.nlm.nih.gov/19470647/)
[@louvi2006]: [Louvi et al., NOTCH3 dominant-negative effects (2006)](https://pubmed.ncbi.nlm.nih.gov/20034186/)
[@andersen2010]: [Andersen et al., NOTCH3 proteolysis in CADASIL (2010)](https://pubmed.ncbi.nlm.nih.gov/20602941/)
[@rost2008]: [Rost et al., Vascular pathology in CADASIL (2008)](https://pubmed.ncbi.nlm.nih.gov/23150969/)
[@pires2017]: [Pires et al., Cerebral autoregulation in CADASIL (2017)](https://pubmed.ncbi.nlm.nih.gov/25634162/)
[@zhao2017]: [Zhao et al., Neurovascular unit in CADASIL (2017)](https://pubmed.ncbi.nlm.nih.gov/28487132/)
[@holtmannspotter2012]: [Holtmannspotter et al., DTI in CADASIL (2012)](https://pubmed.ncbi.nlm.nih.gov/22114047/)
[@van2013]: [van den Brink et al., Perfusion imaging in CADASIL (2013)](https://pubmed.ncbi.nlm.nih.gov/23380726/)
[@youssof2014]: [Youssof et al., SWI for microbleeds in CADASIL (2014)](https://pubmed.ncbi.nlm.nih.gov/24809787/)
[@wollenweber2016]: [Wollenweber et al., PET imaging in CADASIL (2016)](https://pubmed.ncbi.nlm.nih.gov/25735961/)