[Cheilognathopalatoschisis: its classification and epidemiology].

This article presents a survey of the currently used classification of primary and secondary cleft formations especially from the gentic view. In connection with frequency data a clear distinction is required for the terms: incidence, prevalence and presence. Epidemiologic data, particularly from European countries, are discussed and the conclusion drawn that the data available so far largely represents approximate values. Reliable statistic data are a prerequisite for the evaluation of effect of possible future prevention.