[Cholesterol and development].

The teratogenic action of distal inhibitors of cholesterol synthesis has been known for some time. The induced malformations are of a particular type: they include holoprosencephalies. Recently these observations have solicited increased interest due to: 1/ the discovery in 1993 of a similar form of inhibition of cholesterol synthesis which is responsible for a human malformation syndrome, Smith-Lemli-Opitz; 2/ the demonstration of the involvement of the Sonic Hedgehog gene in normal development of prosencephalon and the description of the mode of action of the protein Shh: autoprocessing followed by "cholesterolisation".