[Joubert's syndrome: report of 12 cases]

Joubert syndrome is a rare autosomal recessive disorder whose main clinical signs are hypotonia, ataxia, mental retardation, abnormal eye movements and a respiratory pattern of alternating tachypnea-apnea during first months of life. The most characteristic imaging features are elongation and thinning of the pontomesencephalic junction with deepening of the interpeduncular fosse, thickening of the superior cerebellar peduncles, hypoplasia of the vermis and incomplete fusion of the halves of the vermis, creating a sagittal vermic cleft. The first three findings are components of the molar tooth sign .

Our aim was to review the clinical features and the neuroradiological findings in 12 children with clinical diagnosis of Joubert syndrome, along with the attempt to correlate clinical and radiological findings.

We performed a retrospective study, and cerebral magnetic resonance imaging was achieved in all cases.

All the children have mental retardation, hypotonia, ataxia and oculomotor abnormalities. Other clinical findings are respiratory rhythm abnormalities, abnormal retinal pigmentation, mouth-tongye-facial dyskinesias, ptosis, polydactyly, scoliosis, congenital heart defects, polycystic kidneys and seizures. All patients have agenesis of the vermis and the molar tooth sign is present in nine patients. Five children have other associated cerebral malformations.

In the absence of a biochemical or genetic marker for the Joubert syndrome, we need to have a group of patients with homogeneous clinical and neuroradiological characteristics, in order to avoid an overlap with other syndromes. According to our experience and the review of the literature, we believe that the following should be considered as major diagnostic criteria for Joubert syndrome: hypotonia, ataxia, mental retardation, oculomotor apraxia and the molar tooth sign . Supporting clinical features are: abnormal respiratory pattern, retinal pigmentation, renal abnormalities and facial dysmorphism.