On the diagnosis of CADASIL

Area of Science:

• Neurology
• Genetics
• Pathology

Background:

• Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is a rare genetic disorder affecting small blood vessels in the brain.
• Diagnosis is often delayed due to overlapping clinical features with other neurological conditions.
• Notch3 gene mutations are the primary cause of CADASIL.

Purpose of the Study:

• To evaluate the diagnostic utility of clinical, immunohistochemical, and molecular methods for CADASIL.
• To assess the accuracy of skin biopsies in diagnosing CADASIL.
• To identify novel Notch3 mutations associated with CADASIL.

Main Methods:

• Analysis of clinical data, skin biopsies (immunohistochemistry), and Notch3 gene sequencing in 200 suspected CADASIL patients.
• Detailed reporting of 93 biopsies and 190 molecular studies.
• Comparison of diagnostic test results with confirmed CADASIL cases.

Main Results:

• Eighteen pathogenic Notch3 mutations were identified in 67 patients, including six new mutations.
• Clinical features alone were insufficient to differentiate CADASIL from similar syndromes.
• Skin biopsy sensitivity was 97.7% and specificity 56.5%, improving to 100% and 81.5% with a family history.

Conclusions:

• Clinical diagnosis of CADASIL is unreliable and requires confirmatory testing.
• Immunohistochemical and molecular analyses are essential for definitive CADASIL diagnosis.
• Skin biopsies are highly sensitive but require careful interpretation, especially in sporadic cases.