A link between EC dysfunction and OPC maturation arrest with myelin abnormalities is also found in the rare and familial SVD cathepsin A-related arteriopathy with strokes and leukoencephalopathy (CARASAL) [10], suggesting that there may be other molecular deficits affecting this crosstalk that are hitherto unrecognised causes of sporadic SVD. The gene discussed is CTSA; the disease is stroke disorder.