ABSTRACT
A large number of agents are known which might interfere with the normal development of organ systems during embryogenesis.1,4 The underlying mechanisms of this interference is poorly understood in most cases. Characteristically, during organogenesis, different organs of the embryo show distinct periods of greatest sensitivity to the action of the teratogen. These phases of greatest sensitivity are called the ‘teratogenetic period of determination’.5 The typical patterns of some syndromes can be explained by an overlap of these phases during embryological development.
