page_title: Frontonasal dysplasia
section_title: Signs and symptoms
hierarchical_section_title: Frontonasal dysplasia / Signs and symptoms
caption_attribution_description: English: Tessier classification. Left: boney clefts, right: soft tissue clefts
context_page_description: Frontonasal dysplasia is a congenital malformation of the midface.
  For the diagnosis of FND, a patient should present at least two of the following characteristics: hypertelorism, a wide nasal root, vertical midline cleft of the nose and/or upper lip, cleft of the wings of the nose, malformed nasal tip, encephalocele or V-shaped hair pattern on the forehead.
  The cause of FND remains unknown. FND seems to be sporadic and multiple environmental factors are suggested as possible causes for the syndrome. However, in some families multiple cases of FND were reported, which suggests a genetic cause of FND.
context_section_description: Midfacial malformations can be subdivided into two different groups. One group with hypertelorism, this includes FND. The other with hypotelorism (a decreased distance between the eyes), this includes holoprosencephaly (failure of development of the forebrain). In addition, a craniofacial cleft can be classified using the Tessier classification. Each of the clefts is numbered from 0 to 14. The 15 different types of clefts are then subdivided into 4 groups, based on their anatomical position in the face: midline clefts, paramedian clefts, orbital clefts and lateral clefts. FND is a midline cleft, classified as Tessier 0/14. 
  Besides this, the additional anomalies seen in FND can be subdivided by region. None of these anomalies are specific for the syndrome of FND, but they do occur more often in patients with FND than in the population. The anomalies that may be present are:
  Nasal: mild anomalies to nostrils that are far apart and a broad nasal root, a notch or cleft of the nose and accessory nasal tags.
  Ocular: narrowed eye slits, almond shaped eyes, epicanthal folds (extra eyelid tissue), epibulbar dermoids (benign tumors of the eye), upper eyelid colombas (full thickness upper eyelid defects), microphthalmos (one or two small eyes), congenital cataract and degeneration of the eye with retinal detachment.
  Facial: telecanthus (an increased distance between the corners of the eye), a median cleft of the upper lip and/or palatum, and a V-shaped hairline.
  Others: polydactyly (an excess of fingers or toes), syndactyly (fused fingers or toes), brachydactyly (short fingers and/or toes), clinodactyly (bending of the fifth fingers towards the fourth fingers), preauricular skin tags, an absent tragus, low set ears, deafness, small frontal sinuses, mental retardation, encephalocele (protrusion of the brain), spina bifida (split spine), meningoencephalocele (protrusion of both meninges), umbilical hernia, cryptorchidism (absence of one or two testes) and possibly cardiac anomalies.
  The clefts of the face that are present in FND are vertical clefts. These can differ in severity. When they are less severe, they often present with hypertelorism and normal brain development.
  Mental retardation is more likely when the hypertelorism is more severe or when extracephalic anomalies occur.
caption: Tessier classification. Left: bony clefts, Right: Soft tissue clefts.
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