Joubert syndrome
Incidence
The syndrome is familial with some cases of parental consanguinity and is transmitted as autosomal recessive trait.
Clinical Characteristics
Joubert syndrome may present with hypotonia and decreased dynamic tone, hyperventilation alternating with apnea, and abnormal eye movements during the neonatal period. Joubert syndrome is characterized by agenesis or hypoplasia of the cerebellar vermis. The posterior fossa is normal or small in size. The tentorium is not high. Other central nervous system abnormalities that often present with Joubert syndrome are dysplasia or heterotopia of the cerebellar nuclei, absence of the pyramidal decussation, and histological abnormalities of the inferior olivary nuclei, trigeminal tract, solitary fascicle, and dorsal column nuclei. Joubert syndrome presents in the neonatal period with hyperpnea alternating with apnea. Abnormal eye movements may be present. These neonates also have flaccid hypotonia. The diagnosis is established by MRI. The MRI shows complete or partial absence of the cerebellar vermis and a normal or small posterior fossa. In summary there is partial or complete absence of the cerebellar vermis, episodic tachypnea, neonatal apnea, jerky eye movements, hypotonia, ataxia, impaired equilibrium, and mental handicap. Leber amaurosis (blindness with normal optic fundi and brain and kidney abnormalities) may be associated.
Precipitants
none
Provocation Tests
none
Diagnostic Procedures
The diagnosis is established by MRI.