Frontonasal dysplasia

Frontonasal dysplasia, also known as median cleft face syndrome, is a rare disorder characterized by midline defects involving the face, head, and central nervous system.

Epidemiology

Frontonasal dysplasia is considered to be a very rare condition, with approximately 100 cases having been reported in the literature ⁸.

Clinical presentation

Clinical features are extremely varied and can be present in any combination or severity. Commonly described features include ^8,9:

• face and head
  • hypertelorism
  • cleft lip
  • cleft palate
  • absence of the nasal tip
  • widow's peak frontal hairline
• central nervous system 
  • cranium bifidum occultum (cleft skull)
  • ethmoidal cephalocele
  • agenesis of the corpus callosum
  • ventriculomegaly
  • interhemispheric cyst

Pathology

The exact pathogenesis is unknown but it is possible that a primary neural crest migration defect or a fetal ischemic episode inhibiting cell migration act as an initial event. Some authors consider this condition to be a less severe manifestation of the holoprosencephaly spectrum.

Genetics

Most cases are sporadic although rare familial cases have been described ⁸.

Radiographic features

Radiographic features, similar to the clinical presentation, are highly variable and can be detected prenatally. See individual articles for detailed characteristics of each possible defect.

Treatment and prognosis

No specific treatment is available. Surgical intervention is often required for midline facial defects ⁹.

History and etymology

The term 'frontonasal dysplasia' was introduced by H O Sedano et al. in 1970 to describe a group of patients with midline facial clefting ⁷.