Objective: Using the systematic review method, (1) to identify the investigations of the parental dentocraniofacial phenotype in orofacial clefting, (2) synthesize the data to derive a model of the phenotypic features that will assist in the identification of cleft morphogenes, and (3) make recommendations for the future global strategy for researching the parental craniofacial phenotype in orofacial clefting.
Search strategy: The Cochrane, Medline (via PubMed and OVID platforms [1966 to December 2006]), Embase, CINAHL, and ASKSAM Orthodontic Reference Database (1950-1997) databases were searched using a combination of the following keywords: microform, parent, craniofacial, dental, and cleft. All published articles were reviewed. There were no exclusions of non-English reports. Of the 36 studies identified using this strategy, 26 met the inclusion criteria. DATA ABSTRACTION/SYNTHESIS: The statistically significant data were abstracted using a pro forma, and the methodological quality of the selected studies was evaluated using a checklist. There was considerable heterogeneity among the studies, and therefore it was not possible to synthesize the data. We were, however, able to collate the data.
Results/conclusions: (1) The craniofacial phenotype possessed by parents of children with orofacial clefting is distinctive when compared with that of the noncleft population. (2) There is insufficient evidence to produce a model of the phenotypic features to assist in the search for orofacial clefting morphogenes. (3) The pattern of expression of the phenotypic features identified to date supports the contention that there are differences in the inheritance of cleft lip with or without cleft palate and isolated cleft palate. Progress in this field is affected by extreme heterogeneity in etiology of cleft lip with or without cleft palate, as well as heterogeneity in study design. (4) Subphenotyping using features such as microforms should be employed to reduce the heterogeneity and to improve the power of future genetic investigations and will also assist in clinical management and genetic counseling for families.