Dandy walker malformation, isolated
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Summary
Dandy-Walker malformation (DWM) is the association of three signs: hydrocephalus, partial or complete absence of the cerebellar vermis, and posterior fossa cyst contiguous with the fourth ventricle. The incidence of DWM is around 1.0 per 100,000 live births, being 1.24 for males and 0.78 for females. DWM was shown to represent 3.5% of cases of infantile hydrocephalus. In case of normal communication between the fourth ventricle and arachnoid spaces, some authors have proposed a Dandy-Walker variant malformation, but this is debated. The defect first was thought to be atresia of the foramina of Luschka and Magendie but later the anomaly was found to not necessarily be due to foraminal atresia since some cases had patent foramina. Patients present early in life with hydrocephalus associated with bulging occiput. Posterior fossa signs such as cranial nerve palsies, nystagmus and ataxia are common. Radiologically, patients show elevated imprint of the transverse sinuses with thinning and bulging of the bones of the posterior fossa. The anomaly is etiologically heterogeneous, and a review of the literature has shown that, according to the family history and associated anomalies, the Dandy Walker malformation may be autosomal recessive in a number of multiple malformations syndromes (eg Meckel or Joubert syndrome), autosomal recessive in case of inborn errors of metabolism (eg CDG syndrome), autosomal dominant (eg G syndrome), X-linked recessive (eg Aicardi syndrome), sporadic, included in chromosomal aberrations, or of teratogenic origin (maternal diabetes, maternal viral infection, maternal medications). Recurrence risk is low (on the order of 1 to 5%) when DWM is not associated with a mendelian disorder. There appears to be an increased frequency of associations with congenital heart disease, cleft lip/palate and neural tube defects. Prenatal diagnosis is possible by ultrasonography that may show posterior fossa cyst and cerebellar vermis agenesis. Fetal MRI may confirm the diagnosis. *Author: Orphanet (December 2004)*.
Clinical signs
- Basilary impressions
- Dandy-walker anomaly
- Prominent occiput
- Frontal bossing
- Abnormal urinary tract/renal function
- Antenatal exposure : influenza
- Antenatal exposure : rubella
- Autosomal dominant inheritance
- Autosomal recessive inheritance
- Cardiac anomalies
- Cleft palate
- Corpus callosum/pellucidum agenesis
- Encephalocele/exencephaly
- Submicroscopic deletion/duplication
- Tetralogy of Fallot
- X-linked recessive inheritance
Update : 15/04/2007
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