We report on 14 fetuses from 10 families with the autosomal recessive syndrome of proliferative vasculopathy and hydranencephaly-hydrocephaly (Fowler syndrome). In four families sibs were affected and in six the parents were consanguineous. Antenatal ultrasonography showed hydrocephaly in all except two fetuses, but hydranencephaly was diagnosed in only one case. Postural abnormalities were seen in 10 fetuses and structural brain abnormalities were suspected in 3. At autopsy the cerebral cortex appeared as a translucent membranous structure (hydranencephaly) in most fetuses. However, in one case, the ventricles were dilated but the cortical mantle was relatively well preserved. Histology of the brain showed the characteristic glomeruloid vascular proliferation of Fowler syndrome in all cases, but with variable extent of involvement of the central nervous system. Dystrophic calcification and necrosis were always present. Extra-cranial anomalies included micrognathia (10 fetuses), cleft palate (1 fetus), cystic hygroma (2 fetuses), joint contractures (12 fetuses), and pterygia (11 fetuses). The typical proliferative vasculopathy was never observed outside the central nervous system and karyotypes were normal in the 10 fetuses studied. Fowler syndrome should be considered in the differential diagnosis of lethal multiple pterygium syndrome, fetal akinesia, and hydrocephalus in addition to classical hydranencephaly. Autopsy and study of the brain are essential to differentiate autosomal recessive Fowler syndrome from other causes of hydrocephaly and hydranencephaly, which may have a lower recurrence risk.