title: Epidemiological studies on the frequency of clefts in Europe and world-wide.
abstract: BACKGROUND
  Most textbooks present data on the various frequencies of clefts in different human "races". This was studied in more detail.
  
  
  METHODS
  In a major literature study the frequencies of clefting reported in more than 100 publications were studied and the following data was collected: Incidences of clefts in Mongolians, Caucasians and Negroids; relative frequencies of clefts of the primary (and secondary) palate versus that of clefts of the secondary palate (only); data on cleft location (right, left, bilateral) and on genders affected.
  
  
  RESULTS
  There was most confusing data on incidences in the different "races" whilst all other data was rather consistent: complete clefts (i.e. primary plus secondary palate affected) were most common with left sided ones being reported most often; males were more prone to have a cleft of the primary palate than females and females were more often affected by clefts of the secondary palate than males.
  
  
  CONCLUSIONS
  The types of data bases having been evaluated varied from report to report indicating that today's data pools are of different qualities. Regional or national registries are necessary to collect reliable data with strict definitions applied in all countries.
authors.affiliation: Rostock Interdisciplinary Center for Clefts of Lip, Alveolus and Palate and Craniofacial Anomalies, Rostock, University, Germany. karsten.gundlach@med.uni-rostock.de
authors.forename: Karsten K H
authors.initials: KK
authors.lastname: Gundlach
authors.forename: Christina
authors.initials: C
authors.lastname: Maus
mesh_terms: D044383:Black People; D002971:Cleft Lip / Q000453:epidemiology* / Q000208:ethnology; D002972:Cleft Palate / Q000453:epidemiology* / Q000208:ethnology; D005060:Europe / Q000453:epidemiology / Q000208:ethnology; D005260:Female; D006801:Humans; D008297:Male; D017678:Sex Distribution; D044465:White People