CADASIL

Overview

CADASIL, short for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, is an inherited disease of the brain’s small arteries caused by a disease-causing variant in one copy of the NOTCH3 gene. The altered NOTCH3 protein accumulates around vascular smooth-muscle cells and pericytes—the support cells that keep small blood vessels working—causing progressive vessel-wall damage, reduced blood-flow regulation, white-matter injury, migraine with aura in some people, recurrent small strokes, mood symptoms, and cognitive decline. Severity varies substantially by the specific variant and family; in classic, more severe disease, disability commonly develops in mid-to-late adulthood. CADASIL GeneReviews

There is currently no approved treatment that removes the causal NOTCH3 abnormality, stops CADASIL progression, or restores already lost brain tissue. Care is therefore preventive and supportive: rigorous control of blood pressure and other vascular risks, smoking avoidance, treatment of migraine and mood symptoms, rehabilitation after stroke, and individualized decisions about antiplatelet medicines after ischemic stroke or transient ischemic attack. Evidence for stroke-prevention drugs specifically in CADASIL remains limited, and antiplatelets are generally not recommended solely for primary prevention in people who have not had a stroke. AHA scientific statement

Scope of Recent Research (2020–present)

Research since 2020 has become more mechanistic and translational, concentrating on whether CADASIL can be altered by preventing toxic NOTCH3 aggregation, clearing existing extracellular NOTCH3 deposits, correcting or bypassing harmful variants, preserving vascular smooth-muscle cells, and creating biomarkers suitable for early clinical trials. The field has generated credible disease-modifying leads in cells and mouse models, but no candidate has yet entered a therapeutic clinical trial in people; thus, a curative therapy remains an early-stage goal rather than a near-term clinical option. Protein aggregates drive arterial pathology NOTCH3 aggregation inhibitors

Major Breakthroughs and Emerging Therapies

Aggregation-targeted immunotherapy. The most mature recent therapeutic concept is to target abnormal extracellular NOTCH3 (NOTCH3-ECD) deposits with an immune response. In a 2023 study, repeated active immunization of a CADASIL mouse model with aggregated NOTCH3 protein reduced NOTCH3 deposition around brain capillaries by approximately 38–48%, lowered circulating NOTCH3-ECD, and did not produce evident retinal smooth-muscle loss, inflammation, neuronal injury, or kidney injury during the study period. This is an important proof of principle that the deposited protein can be targeted, but it is not yet evidence that vaccination prevents stroke, cognitive decline, or disability in people. Active NOTCH3 immunotherapy in mice

Lowering or preventing formation of both mutant and normal NOTCH3 aggregates. A 2024 mouse study substantially clarified the biology of the disease: mutant NOTCH3-ECD can recruit normal, wild-type NOTCH3-ECD into deposits, and reducing wild-type NOTCH3 by one copy lessened arterial NOTCH3 accumulation and vascular smooth-muscle pathology. The finding shifts therapeutic attention toward carefully calibrated NOTCH3-lowering approaches, rather than approaches that address only the mutant protein; however, normal NOTCH3 is needed for arterial smooth-muscle development and maintenance, so broad suppression could itself be harmful. Protein aggregates drive arterial pathology

Selective NOTCH3 inhibitors and small molecules. In 2026, researchers reported cell-free biochemical and cell-based assays showing that certain CADASIL-mutant receptors form high-molecular-weight aggregates only in the presence of wild-type NOTCH3 receptors. They also identified NOTCH3-selective peptide-based inhibitors that blocked receptor aggregation and mutation-associated NOTCH3 signaling in laboratory models. This supplies a potentially drug-like route to treatment, but the compounds have not yet been shown to reach brain vessels safely, preserve essential NOTCH3 function, or improve disease outcomes in animals or people. NOTCH3 aggregation inhibitors

RNA and gene-directed approaches. Antisense oligonucleotide strategies remain conceptually attractive because many CADASIL variants cluster in exons encoding the early epidermal-growth-factor-like repeats of NOTCH3. The aim is either to skip a mutation-containing exon while retaining a functional receptor or to selectively reduce the disease-causing transcript. Recent mechanistic results strengthen the rationale for allele-aware NOTCH3 lowering, but delivery to the vascular smooth-muscle cells and pericytes throughout the brain, long-term dosing, and avoiding loss of normal NOTCH3 signaling remain unsolved. Protein aggregates drive arterial pathology CADASIL therapeutic approaches review

Clinical Trials and Experimental Approaches

As of October 10, 2026, the most prominent current registered CADASIL studies are natural-history and trial-readiness programs rather than phase 1–3 therapeutic trials. The U.S. CADASIL Consortium study, NCT05677880, is a recruiting, observational study sponsored by the University of Wisconsin–Madison with a target enrollment of 660 participants. It follows people with symptomatic and presymptomatic NOTCH3 variants and controls using clinical examinations, cognitive testing, MRI, and blood samples, with estimated completion in August 2027. Its primary value is to identify early disease markers and endpoints that can make future treatment trials feasible. NCT05677880 study record

Other infrastructure studies include the Fujian Medical University CADASIL Registry Study, NCT04310098, an observational prospective registry sponsored by Bin Cai that began in March 2020 and plans to enroll 1,000 participants, including asymptomatic carriers and relatives. Beijing Tiantan Hospital is also sponsoring NCT06512376, a hereditary cerebral small-vessel-disease registry and trial-ready cohort that includes CADASIL. Neither registry reports a disease-modifying intervention or posted therapeutic outcome. NCT04310098 registry NCT06512376 trial-ready cohort

Methodologies and Scientific Approaches

Researchers combine genetically engineered mouse models, human cell systems, biochemical aggregation assays, and advanced vessel imaging. Recent work used distinct mouse lines carrying a CADASIL-associated NOTCH3 mutation with different amounts of normal NOTCH3, thick brain sections with three-dimensional imaging to quantify smooth-muscle loss, RNA sequencing of arterial tissue, and genetic reduction of wild-type NOTCH3 to test whether deposits themselves drive pathology. Protein aggregates drive arterial pathology

Human research increasingly focuses on biomarkers and trial endpoints: serial MRI, neuropsychological testing, blood collection, retinal imaging, and molecular measurements of NOTCH3-related proteins. A 2025 study of Korean and Japanese cohorts found that serum NOTCH3-ECD did not reliably distinguish CADASIL from healthy controls or track clinical or MRI severity, illustrating why biomarker validation in large, longitudinal cohorts is necessary before a marker can serve as a surrogate endpoint for a cure trial. Serum NOTCH3-ECD study NCT05677880 study record

Leading Institutions and Funding

Leading academic groups include Inserm and Université Paris Cité, where Anne Joutel’s team has driven mechanistic mouse research; Leiden University Medical Center, which has contributed to NOTCH3 biology and selective inhibitor studies; Karolinska Institutet, which led the active-immunization study; and the University of Wisconsin–Madison and its U.S. CADASIL Consortium collaborators, which are building the longitudinal clinical-trial infrastructure. The 2024 arterial-pathology study was supported by French National Research Agency grants, U.S. National Institutes of Health awards, the Leducq Foundation’s BRENDA network, and the Fondation pour la Recherche Médicale. Protein aggregates drive arterial pathology Active NOTCH3 immunotherapy in mice NOTCH3 aggregation inhibitors

Patient-led organizations are also materially shaping the pipeline. CureCADASIL has funded projects ranging from patient-derived vessel-on-chip models to NOTCH3 immunotherapy and small-molecule conformational inhibitors; examples include a $109,856 2024 award to Helena Karlström at Karolinska Institutet and a $101,776 2025 award to Michael Wang at the University of Michigan. The U.S. Food and Drug Administration separately awarded the University of Wisconsin–Madison $5 million over four years in fiscal year 2024 to evaluate retinal imaging biomarkers in CADASIL, a program intended to improve future therapeutic-trial design. CureCADASIL-funded research FDA rare neurodegenerative disease grants

Strengths, Limitations, and Challenges

The major strength of current research is convergence on a plausible, measurable disease mechanism: abnormal NOTCH3-ECD accumulation is not merely a diagnostic byproduct but appears to be a major driver of arterial smooth-muscle-cell loss in clinically relevant mouse models. This makes aggregate reduction, prevention of mutant–wild-type receptor interactions, and precisely targeted NOTCH3 modulation rational therapeutic strategies. Active immunization and selective inhibitors provide independent evidence that the aggregation process can be modified experimentally. Protein aggregates drive arterial pathology Active NOTCH3 immunotherapy in mice NOTCH3 aggregation inhibitors

The principal limitations are translational. Mouse and cell models cannot fully reproduce decades of human small-vessel injury, and a reduction in deposits does not yet prove prevention of stroke or dementia. Systemic inhibition or lowering of NOTCH3 may injure normal arteries; vaccine approaches may have variant-specific efficacy or unforeseen immune risks; and RNA therapies must reach difficult-to-access vascular cells across the brain. Finally, CADASIL is rare and clinically variable, so adequately powered trials will require international recruitment, validated biomarkers, and endpoints sensitive enough to detect benefit before irreversible injury occurs. CADASIL GeneReviews Serum NOTCH3-ECD study

Outlook and Future Directions

CADASIL research is closer than it was in 2020 to a mechanism-based treatment, but not yet close to a demonstrated cure. The next milestones to watch are confirmation that NOTCH3 aggregate-targeting therapies improve vascular function and brain injury in multiple animal models; development of delivery systems that can safely reach brain vascular cells; validation of MRI, retinal, and blood biomarkers in longitudinal cohorts; and initiation of a first-in-human trial of an aggregation-targeted, RNA-directed, or selective NOTCH3-modulating therapy. Until those milestones are met, the most realistic near-term objective is a treatment that slows or prevents progression when given early, rather than reversal of established neurological disability. NCT05677880 study record Protein aggregates drive arterial pathology

References

• CADASIL GeneReviews — GeneReviews®, 2019, updated periodically.
• AHA scientific statement — American Heart Association, 2023.
• Active NOTCH3 immunotherapy in mice — Oliveira et al., 2023.
• Protein aggregates drive arterial pathology — Dupré et al., 2024.
• NOTCH3 aggregation inhibitors — Wang et al., 2026.
• CADASIL therapeutic approaches review — Busse et al., 2025.
• NCT05677880 study record — ClinicalTrials.gov, 2026.
• NCT04310098 registry — ClinicalTrials.gov, 2023.
• NCT06512376 trial-ready cohort — ClinicalTrials.gov, 2026.
• Serum NOTCH3-ECD study — Kim et al., 2025.
• CureCADASIL-funded research — cureCADASIL, 2026.
• FDA rare neurodegenerative disease grants — U.S. Food and Drug Administration, 2026.