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Rhombencephalosynapsis (RS) is a rare malformation of the cerebellum characterised by the association of agenesis (total or partial) of the vermis and fusion of the cerebellar hemispheres.
- Synonym(s): -
- Prevalence: <1 / 1 000 000
- Inheritance: Not applicable
- Age of onset: Infancy, Neonatal, Antenatal
- ICD-10: Q04.3
- OMIM: -
- UMLS: C1866130
- MeSH: -
- GARD: -
- MedDRA: -
The exact prevalence is unknown. A value of 4 in 3000 paediatric magnetic resonance imaging (MRI) scans was reported in one study and around 50 cases have been reported in the literature.
Other cerebral anomalies often associated with RS include fusion of the dentate nuclei, deformation of the fourth ventricle, and fusion of the cerebral peduncles. Supratentorial findings include hydrocephalus, fusion of the thalami, anomalies of the corpus callosum and septo-optic dysplasia. Extracerebral anomalies are also sometimes present: mild dysmorphism, anomalies of the hands and/or feet; ophthalmologic, cardiac, renal, uterine and anal abnormalities and Hirschsprung disease. Syndromic associations have also been reported: Gomez-Lopez-Hernandez syndrome (or cerebellotrigeminodermal dysplasia), RS with bilateral temporoparietal alopecia, anaesthesia in the trigeminal territory and craniostenosis.
The aetiology remains to be confirmed.
Management and treatment
Management is symptomatic, requiring medical, educative, psychological and social care.
The neurological prognosis is variable, ranging from a normal IQ to more or less severe intellectual deficit with ataxia, dysarthria, strabismus and/or nystagmus, behavioural problems (such as obsessive-compulsive and auto-aggressive behaviour).