Cardiovascular and other genetic risk factors have previously been described to contribute to CADASIL disease severity.5 Possibly, EGFr 7–34 PV require a higher additional (vascular) risk-factor profile before causing CADASIL or a small-vessel disease phenotype, whereas an EGFr 1–6 PV alone almost always predisposes to a ‘classical’ CADASIL phenotype. This evidence concerns the gene EGFR and CADASIL.