Joubert Syndrome

At a glance

A genetic disorder characterized by cerebral malformations (vermis and brain stem) resulting in severe coordination (ataxia) and breathing (sleep apnea, hyperpnea) disorders. This medical condition is present during infancy and is characterized by cerebellar ataxia, hyperpnea, sleep apnea, abnormal eye, tongue movements, and myotonia. There is a significant range of mental retardation. The presence of the “molar tooth sign” found in the MRI, in which the cerebellar vermis of the brain is absent or underdeveloped whereas the brain stem is abnormal, is very informative and the Joubert Syndrome must be considered in the differential diagnosis.

Synonyms

Cerebellar Vermis Agenesis Syndrome; Cerebelloparenchymal Disorder Type IV; Chorioretinal Coloboma with Cerebellar Vermis Aplasia; Coloboma, Chorioretinal with Cere­bellar Vermis Aplasia; Joubert-Boltshauser Syndrome; Cerebello-Oculo-Renal Syndrome 1; CORS1.

History

Peroxisomal disease named after Marie Joubert, a Canadian neurologist who reported the first case in 1989, in Montreal.

Incidence

The prevalence is estimated at 1:258,000. However, it is possibly under-estimated as most believe that the true prevalence is closer to 1:100,000.

Genetic inheritance

Autosomal recessive. Gene map locus is 9q34.3.

Pathophysiology

Unknown.

Diagnosis

Typical “molar tooth” sign on axial magnetic resonance imaging (MRI) through the malformed pontomesencephalic junction. Ultrasonographic evaluation is essential to establish the diagnosis, particularly, abdominal and cerebral in the neonatal period.

Clinical aspects

During the neonatal period, variable combinations of central nervous system, eye, and renal abnormalities. Agenesis of the cerebellar vermix with cystic dilatation of the fourth ventricle and poor respiratory control is pathognomonic of this medical condition. Episodes of tachypnea attacks alternating with apneas are frequently seen. Severe psychomotor retardation and ataxia are present. Abnormal eye movements and bilateral coloboma are characteristic of the disease. Abdominal ultrasonographs reveal cortical renal cysts and interstitial renal fibrosis. Other malformations, including polydactyly (fingers and toes), cleft lip/palate, tongue malformations, and seizures, may exist. Renal function may deteriorate. Prognosis is poor.

Precautions before anesthesia

Check respiratory function, perform pulmonary function tests if patient collaboration permits (forced vital capacity [FVC], forced expiratory volume at 1 second [FEV₁]; maximal expiratory flow rate [MEFR], residual volume [RV]). Perform arterial blood gases in room air in all cases. Check renal function by checking electrolytes, blood urea nitrogen, and creatinine. The administration of premedication is unadvised.

Anesthetic considerations

Children with this syndrome have abnormalities of respiratory control as a consequence of neuronal changes in the brain stem and cerebellum. They are extremely sensitive to the respiratory depressant effects of anesthetic agents, including nitrous oxide. Anesthesia using inhalational induction, intermittent positive pressure ventilation, avoidance of opioids, and ...