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]
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]
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]
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]
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]
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]
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 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]
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]
Additional manifestations include: [@joutel2010]
MRI findings are characteristic and essential for diagnosis [13](https://pubmed.ncbi.nlm.nih.gov/10666668/): [@benedito2009]
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]
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]
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]
CADASIL must be distinguished from other small vessel diseases: [@rost2008]
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, 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]
Several other genetic conditions can mimic CADASIL, including: [@holtmannspotter2012]
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]
Aggressive management of vascular risk factors is essential: [@youssof2014]
Several therapeutic approaches are under investigation: [@wollenweber2016]
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.
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:
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.
Current research focuses on:
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/).
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/).
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.
Historical therapeutic approaches that have been evaluated include:
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/).
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/).
While CADASIL is genetically determined, vascular risk factors modify disease expression:
The variable expressivity of CADASIL suggests genetic modifiers:
Although CADASIL typically presents in adulthood, subtle findings can be detected earlier:
CADASIL progressively impacts daily functioning through:
CADASIL imposes significant economic costs:
Identification of reliable biomarkers is crucial for clinical trials:
Gene therapy strategies being explored include:
[@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/)