The Pierre Robin syndrome reassessed in the light of recent research.

For many years clinicians have known the coincidental presentation of micrognathia, glossoptosis and cleft palate as the Pierre Robin syndrome. In conferences in 1974 and 1975 the term "Anomalad" was introduced which by definition is a primary malformation with superimposed secondary structural changes and the Pierre Robin syndrome became known as the Robin Anomalad. The concept was based on experimental observations available at that time. However, since that date further studies have demonstrated that administration of drugs to pregnant female rodents can produce coincidental failure of normal development of both mandible and palate. In the light of this work a critical review is made of the evidence upon which the mechanistic view of the condition evolved and an alternative hypothesis developed. From animal experimentation it can be argued that the nature of the condition is not mechanical and is more likely to be metabolic. Indeed, confirmatory evidence in man has recently been presented from Finland. If this is the case it may be erroneous to consider the Robin malformations as an "Anomalad" and mandibular maxillary agenesis would probably be a more accurate term.