Joubert syndrome is a rare autosomal recessive genetic disorder that affects the cerebellum, an area of the brain that controls balance and coordination.

[5] Most of the signs and symptoms of the Joubert syndrome appear very early in infancy with most children showing delays in gross motor milestones.

Other malformations such as polydactyly (extra fingers and toes), cleft lip or palate, tongue abnormalities, and seizures may also occur.

[8][9][10] Those with this syndrome often exhibit specific facial features such as a broad forehead, arched eyebrows, ptosis (droopy eyelids), hypertelorism (widely spaced eyes), low-set ears, and a triangle shaped mouth.

[11] Several mutations have been identified in individuals with Joubert syndrome (JBTS) which allowed for classification of the disorder into subtypes.

[14] The disorder is characterized by the absence or underdevelopment of the cerebellar vermis and a malformed brain stem (molar tooth sign), both of which can be visualized on a transverse view of the head MRI scan.

The syndrome is associated with progressive worsening of the kidneys, the liver, and the eyes and thus requires regular monitoring.

[22] The underlying cause of the ciliopathies may be a dysfunctional molecular mechanism in the primary cilia structures of the cell, organelles which are present in many cellular types throughout the human body.

The cilia defects adversely affect "numerous critical developmental signaling pathways" essential to cellular development and thus offer a plausible hypothesis for the often multi-symptom nature of a large set of syndromes and diseases.