Many theories have been advanced concerning the causes of cleft palate. Early theories attempted to explain this developmental defect by abnormal mechanical influences. Abnormal pressure of the mandible and tongue,1 and interposition of extremities,2 of tumors3 or of supernumerary teeth4 were blamed for the failure of union of the various parts which constitute the normal palate. Amniotic pressure and amniotic bands received special attention as possible causes of facial clefts.5 Hydrocephalus causing broadening of the base of the skull was also mentioned.6 None of these theories could be sufficiently supported, and it is thought today that the conditions once considered as causative were only accidental or collateral abnormalities found in the affected persons.
Reports of familial occurrence of cleft lip and palate date back to the eighteenth century,7 and numerous instances of families in which these malformations occurred repeatedly and through several generations
WARKANY J, NELSON RC, SCHRAFFENBERGER E. CONGENITAL MALFORMATIONS INDUCED IN RATS BY MATERNAL NUTRITIONAL DEFICIENCYIV. CLEFT PALATE. Am J Dis Child. 1943;65(6):882–894. doi:10.1001/archpedi.1943.02010180058007