Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary angiopathy caused by mutations in the NOTCH3 gene. The clinical course is highly variable. Little is known about the long-term prognosis and the causes of death in CADASIL patients. Likewise, the impact of gender and NOTCH3 genotype on disease progression remains largely unexplored. We identified 411 subjects (196 men, 215 women) with a definite diagnosis of CADASIL. Age at onset for stroke, immobilization and death as well as the causes of death and clinical status at onset of the cause of death were determined systematically. Weibull regression models were used to calculate times to event, with gender and NOTCH3 genotype as covariates. At the time of the study, 73 patients had died. The median age at onset for stroke was 50.7 years [95% confidence interval (CI) = 48.2-53.1 years] in men and 52.5 years (95% CI = 50.0-54.9 years) in women (P = n.s.). The median ages at onset for inability to walk without assistance [men 58.9 years (95% CI = 56.6-61.3 years); women 62.1 years (59.7-64.4 years)], bedriddenness [men 62.1 years (59.6-64.7 years), women 66.5 years (63.9-69.1 years); and death [men 64.6 years (61.7-67.6 years); women 70.7 years (67.6-73.9 years)] were significantly lower in men than in women (all P < or = 0.01). The median survival time of men was significantly shorter than expected from German life tables (64.6 versus 69.3 years, P = 0.01). In contrast, the median survival time of women was not significantly reduced (70.7 versus 72.2 years). The C117F mutation was associated with a lower age at death and the C174Y mutation with a lower age at onset for stroke, immobilization and death (adjusted P values <0.05). At onset of the cause of death, 78% of the subjects were completely dependent. Sixty-three per cent were confined to bed. Pneumonia was the most frequent cause of death (38%), followed by sudden unexpected death (26%) and asphyxia (12%). We conclude that male sex is a risk factor for early immobilization and death in CADASIL. Our findings suggest possible genotype-phenotype correlations with regard to disease progression. The data presented may serve as source material for counselling CADASIL patients and for designing future interventional trials.