Joubert syndrome is a rare autosomal recessive disorder characterized by a specific congenital malformation of the cerebellar vermis. Diagnostic criteria for it include hypotonia, ataxia, episodic hyperpnoea, psychomotor delay, abnormal eye-movement, and the molar tooth sign on magnetic resonance imaging (MRI). We present a 12-month-old boy with Joubert syndrome referred to our hospital because of vertigo. On equilibrium examination, he exhibited left-beating gaze nystagmus, and right-beating horizontal nystagmus, up-beating nystagmus, and alternating nystagmus with a torsional component on positional nystagmus examination. Saccades were preceded by slow eye movement ending with a glissade, and were followed by postsaccadic drift. His smooth pursuit to the left was saccadic, and optokinetic nystagmus gains were reduced. Three months later, his symptoms gradually resolved, his gaze nystagmus nearly disappeared, and only right-beating nystagmus on positional examination was detected.
