COL4A1-Related Brain Small Vessel Disease With Haemorrhage

This observational and diagnostic study aims to better understand the clinical features and biological mechanisms associated with mutations in the COL4A1 and COL4A2 genes, which are known to cause a rare inherited small-vessel disease affecting the brain and other organs. These mutations can lead to a wide range of symptoms involving the brain, eyes, heart, blood vessels, kidneys, and muscles, and affected individuals within the same family may show very different clinical manifestations. The study will systematically collect clinical and diagnostic information from individuals with confirmed COL4A1/COL4A2 mutations and their first-degree family members, including both affected and unaffected relatives. Family members who carry, or may carry, the mutation will be offered non-invasive eye and heart examinations to detect early or previously unrecognized organ involvement. In addition, blood samples will be analyzed to study the activity of specific enzymes called matrix metalloproteinases (MMP2 and MMP9), which are thought to play a role in blood vessel damage in this condition. By linking genetic findings, clinical features, and laboratory data, the study seeks to clarify how these mutations cause disease and to identify early signs of organ involvement. The overall goal of the study is to improve early diagnosis, guide the development of routine multi-organ screening strategies for affected individuals and families, and support future research toward targeted treatments.

The TAG-SVD enrolled patients with clinical and neuroimaging features of cerebral small vessel disease (CSVD). All enrolled patients will receive next-generation sequence (NGS) with probes designed to target five candidate CSVD genes, and patients will be divided into genetic or non-genetic groups accordingly. Their clinical features and outcome will be followed for at least 2 years.