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At a glance

Syndrome manifested by cleft lip and anterior cleft palate, microcephaly, mental retardation, hypertelorism, bifid uvula, and absence of the nasal septal cartilage.

N.B.: This is also known as holoprosencephaly type I. This medical condition should not be confused with holoprosencephaly type II in which hypotelorism and the possibility of cebocephaly (cyclopia) may be encountered.

Synonyms

Frontonasal Dysplasia Sequence; Median Cleft Face Syndrome; DeMyer Syndrome; Holoprosencephaly Type I.

Incidence

Rare; male-to-female ratio is 2:1; increased paternal and maternal ages at the time of conception.

Genetic inheritance

Most often a sporadic condition limited to the face and head. A dominant form with associated spinal anomalies has been reported; other reports suggest a multifactorial transmission. Translocations involving chromosomes 3, 7, and 11 and four breakpoints have been reported in a 4-year-old boy. For some unknown reason, instances of twinning are greater in families with frontonasal dysplasia than in the general population.

Pathophysiology

Facial dysplasia with dysostosis (craniofacial helix) and clefting. True or primary clefts are caused by the persistence of epithelium between the borders of the facial processes (deficient epithelial cell degeneration).

Diagnosis

Clinical features (wide midline cleft of the facial skeleton, hypertelorism of eyes, and possible coexisting severe deformity of lower extremities) in conjunction with certain roentgenographic findings (anterior cranium bifidum, hypoplastic frontal sinuses, dense calcification of the falx, interhemispheric lipoma) and ophthalmologic examinations (refractive errors, strabismus, nystagmus, and eyelid ptosis).

Clinical aspects

Facies: Frontonasal dysplasia; narrowing of palpebral fissures; hypertelorism; broad nasal root; median nasal groove; absent nasal tip; separated slit-like nares, bifid nose; widow’s peak; strabismus; nystagmus; eyelid ptosis. Skeleton: Tibial aplasia; hallucal polydactyly; varus deformity; anterior cranium bifidum occultum. Other Anomalies: Median cleft palate; encephalocele; duplication of labial frenulum; tetralogy of Fallot; mental retardation (10-15% of patients). In severe cases, the central nervous system may be affected, and there is a mental deficiency. The severity of reported examples can be graded in a logical sequence. The patients may have bifidity of the tip or dorsum of the nose, sometimes in association with a median cleft lip or median notch of the Cupid’s bow and with a duplication of the labial frenulum. Frontonasoethmoidal dysplasia and even transsphenoidal encephalocele with pituitary herniation and orbital hypertelorism are common. The maxilla may show a keel-shaped deformity with rotation of the incisors. A median cleft of the palate may be observed, with other anomalies including mental retardation.

Precautions before anesthesia

Evaluate carefully for difficult laryngoscopy and tracheal intubation. Physical examination directed primarily toward the central nervous system, cardiovascular system (tetralogy of Fallot), lungs, and upper airway. Standard preoperative laboratory examinations are appropriate in most patients (blood chemistries, blood group, hemoglobin, coagulation profile).

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