Subphenotyping and Classification of Cleft Lip and Alveolus in Adult Unoperated Patients: A New Embryological Approach.

Objective: Previously, a new embryological classification was introduced subdividing oral clefts into fusion and/or differentiation defects. This subdivision was used to classify all subphenotypes of cleft lip with or without alveolus (CL±A). Subsequently, it was investigated whether further morphological grading of incomplete CLs is clinically relevant, and which alveolar part is deficient in fusion/differentiation defects.