title: Evaluation and integration of disparate classification systems for clefts of the lip.
abstract: Orofacial clefting is a common birth defect with wide phenotypic variability. Many systems have been developed to classify cleft patterns to facilitate diagnosis, management, surgical treatment, and research. In this review, we examine the rationale for different existing classification schemes and determine their inter-relationships, as well as strengths and deficiencies for subclassification of clefts of the lip. The various systems differ in how they describe and define attributes of cleft lip (CL) phenotypes. Application and analysis of the CL classifications reveal discrepancies that may result in errors when comparing studies that use different systems. These inconsistencies in terminology, variable levels of subclassification, and ambiguity in some descriptions may confound analyses and impede further research aimed at understanding the genetics and etiology of clefts, development of effective treatment options for patients, as well as cross-institutional comparisons of outcome measures. Identification and reconciliation of discrepancies among existing systems is the first step toward creating a common standard to allow for a more explicit interpretation that will ultimately lead to a better understanding of the causes and manifestations of phenotypic variations in clefting.
authors.affiliation: Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute Seattle, WA, USA.
authors.forename: Kathie H
authors.initials: KH
authors.lastname: Wang
authors.affiliation: Center for Clinical and Translational Sciences, Seattle Children's Research Institute Seattle, WA, USA ; Seattle Children's Craniofacial Center Seattle, WA, USA ; Department of Pediatrics (Division of Craniofacial Medicine), University of Washington Seattle, WA, USA.
authors.forename: Carrie L
authors.initials: CL
authors.lastname: Heike
authors.affiliation: Department of Biological Structure (Structural Informatics Group), University of Washington Seattle, WA, USA ; Department of Biomedical Informatics and Medical Education, University of Washington Seattle, WA, USA.
authors.forename: Melissa D
authors.initials: MD
authors.lastname: Clarkson
authors.affiliation: Department of Biological Structure (Structural Informatics Group), University of Washington Seattle, WA, USA.
authors.forename: Jose L V
authors.initials: JL
authors.lastname: Mejino
authors.affiliation: Department of Biological Structure (Structural Informatics Group), University of Washington Seattle, WA, USA ; Department of Biomedical Informatics and Medical Education, University of Washington Seattle, WA, USA.
authors.forename: James F
authors.initials: JF
authors.lastname: Brinkley
authors.affiliation: Seattle Children's Craniofacial Center Seattle, WA, USA.
authors.forename: Raymond W
authors.initials: RW
authors.lastname: Tse
authors.affiliation: Seattle Children's Craniofacial Center Seattle, WA, USA.
authors.forename: Craig B
authors.initials: CB
authors.lastname: Birgfeld
authors.affiliation: Faculty of Medicine, The Cleft Palate Clinic, The Children's Hospital at Westmead, and Discipline of Paediatrics and Child Health, University of Sydney Sydney, NSW, Australia.
authors.forename: David A
authors.initials: DA
authors.lastname: Fitzsimons
authors.affiliation: Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute Seattle, WA, USA ; Seattle Children's Craniofacial Center Seattle, WA, USA ; Department of Pediatrics (Division of Craniofacial Medicine), University of Washington Seattle, WA, USA ; Department of Anatomy and Developmental Biology, Monash University Clayton, VIC, Australia.
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Cox
keywords: classification system; cleft lip; forme fruste; incomplete cleft; ontology; orofacial clefts