Cerebral small vessel disease (SVD) accounts for 20% of all ischaemic strokes, and is often clustered in families. A number of monogenic diseases may underlie these familial forms of SVD. An example of this is CADASIL, where there has been a mutation in the NOTCH3 gene.

Other rare inherited diseases have also been found to produce symptoms similar to those seen in CADASIL, such as migraines, strokes and cognitive impairment. However, the diagnostic tests for these diseases are expensive and not widely available. In addition, there are some families in whom these tests are negative, but are likely to have abnormalities in other genes that have yet to be discovered.

The National Institute for Health Research, Cambridge University and Cambridge University Hospitals NHS Foundation Trust are jointly funding a research project known as BRIDGE. This project aims to uncover the genes underlying these rare causes of SVD, to develop new diagnostic techniques, and to support the development of targeted treatment strategies for these diseases.