Lina Lasri, Samia Obilat, Ibtissam El Bqaq, Lina Belkouchi, Siham El Haddad, Nazik Allali, Latifa Chat
Journal: Medpeer Publisher
ISSN: 3066-2737
Volume: 3
Issue: 8
Date of Publication: 2026/08/15
Joubert syndrome is a congenital ciliopathy defined neuroradiologically by a characteristic
malformation of the pontomesencephalic junction. When accompanied by complete agenesis of
the corpus callosum, it produces a striking combination of infratentorial and supratentorial MRI
signs. We report the imaging findings in an 8-year-old boy referred for brain magnetic
resonance imaging because of clinically suspected macrocephaly. He had no motor or language
delay and no history of seizures, although mild learning difficulties were reported. Renal
evaluation was normal. Magnetic resonance imaging demonstrated complete absence of the
corpus callosum, parallel and widely separated lateral ventricles with the racing-car
configuration, lateral eversion of the frontal horns producing a bull’s-horn appearance,
colpocephaly, and widening of the interhemispheric fissure. At the pontomesencephalic
junction, a deep interpeduncular fossa and thickened, elongated, horizontally oriented superior
cerebellar peduncles, together with vermian hypoplasia, produced the characteristic molar
tooth sign. The combined findings supported a Joubert spectrum disorder associated with
complete callosal agenesis and underscored the value of MRI pattern recognition in a child with
limited neurologic manifestations.
Joubert syndrome; agenesis of the corpus callosum; molar tooth sign; pediatric brain MRI; racing-car sign
Download PDF