Features considered necessary for the clinical diagnosis of classic Joubert Syndrome:
(1) molar tooth sign (MTS) on cranial MRI
(2) hypotonia during infancy
(3) developmental delay or mental retardation (may range from mild to severe)
The molar tooth sign involves 3 components (best seen in horizontal MRI images):
(1) hypoplasia of the midline cerebellar vermis
(2) deepened interpeduncular fossa
(3) elongation of the superior cerebellar peduncles
Supportive finding(s):
(1) irregular breathing during infancy (episodic tachypnea, episodic apnea or both)
(2) abnormal eye movements, such as jerky eye movements, nystagmus, difficulty with smooth visual pursuits, and/or oculomotor apraxia (OMA)
