There are multiple classification systems for<unk> . None of these classification systems have unraveled any genetic factors as the cause of<unk> . Yet, all of them are very valuable in determining the prognosis of an individual. In the subheadings below, the most common classifications will be explained. Sedano classification This is a classification based on the embryological cause of<unk> . De Myer This classification is based on the morphologic characteristics of<unk> , that describes a variety of phenotypes Both of these classifications are further described in table 1. This table originates from the article ‘Acromelic<unk> : further delineation of a subtype with brain malformations and polydactyly (Toriello syndrome)', Verloes et al. Table 1. Phenotypic Classifications of the face in<unk> . DeMyer classification (slightly expanded) Characteristics Type 1 hypertelorism, cranium bifidum, median cleft nose, and cleft prolabium Type 2 hypertelorism, cranium bifidum, and cleft nose but intact prolabium and palate Type 3 hypertelorism, median cleft nose, and median cleft of notched lip Type 4 hypertelorism and median cleft nose Each type may be then subdivided in: Subtype a the two sides of the cleft nose are set apart Subtype b the two sides of the nose remain continuous. The cleft of the nose involves the nasal septum and extends to the tip of the nose Subtype c the cleft does not reach the tip of the nose. hypertelorism is borderline Sedano-Jirásek classification Characteristics Type A hypertelorism, median nasal groove, and absent nasal tip Type B hypertelorism, median groove or cleft face, with or without lip or palate cleft Type C hypertelorism and notching of alae nasi Type D hypertelorism, median groove or cleft face, with or without lip or palate cleft and notching of alae nasi
Frontonasal dysplasia
Craniofrontonasal dysplasia
Oral submucous fibrosis
Hereditary mucoepithelial dysplasia
Nevoid basal-cell carcinoma syndrome
Genodermatosis
Neurofibromatosis
Neurofibromatosis type I