The cerebellar vermis, which is responsible for balance and coordination, is either absent or underdeveloped in people with Joubert syndrome. Additionally, the brain stem is deformed in these patients.

There are not many people that have Joubert syndrome. At most, just one in every 100,000 infants is born with this condition. 

Experts claim that mutations in at least 35 genes result in Joubert syndrome. It is possible to get this disorder through random (with no known family link) or familial means.

Mutations may induce improper cilia formation, which is a hallmark of Joubert syndrome. In healthy individuals, cilia help cells communicate by acting as antennas. However, when cilia become damaged, this can result in faulty cell signaling and reduced motility. To this day, scientists are unsure how this destruction in cilia happens.

In babies, Joubert syndrome is characterized by rapid breathing (hyperpnea), low muscular tone (hypotonia), aberrant eye movements, delayed cerebral development, and difficulty coordinating voluntary muscle movements (ataxia). 

The physical characteristics of certain people with Joubert syndrome may also include the following:

• A cleft in the palate or lip;
• Unique facial features such as a broad forehead, droopy eyelids, eyes spaced wider, ears set lower, and mouth shaped like a triangle;
• Tongue abnormalities.

Other organs susceptible to damage from Joubert syndrome are:

• The retinas of the eyes
• Kidney
• Liver

When diagnosing Joubert syndrome, doctors look at the child’s symptoms and the results of an MRI. In a brain MRI, the characteristic sign of this condition is the “molar tooth sign”. The presence of the molar tooth sign usually informs the doctor that a child may have Joubert syndrome.

Joubert syndrome is diagnosed in a child if they exhibit the following symptoms:

• Inability to learn or adapt normally;
• Infantile hypotonia progresses into infantile ataxia.

Treatment

Treatment for Joubert syndrome varies from patient to patient, based on the unique manifestations of the condition.

Possible therapies for developmental delays include:

• Infant stimulation
• Occupational therapy
• Physical therapy
• Speech therapy

Your child’s symptoms of Joubert syndrome may require frequent visits to various medical professionals, including but not limited to a nephrologist (kidney doctor), neurologist (brain doctor), and ophthalmologist (eye doctor). In the course of the management, they will:

• Track the effects of the disruption on the respective organ system;
• Test to see if the syndrome’s impacts are getting worse over time;
• Offer treatments when available.

A consultation with a geneticist or genetic counselor is also an option where they can verify the definite gene mutations responsible for Joubert syndrome. They can also advise families on whether or not to test additional members for the mutation.

Joubert syndrome cannot be avoided. However, geneticists and genetic counselors can assist with identifying at-risk family members. People can use the data to inform their choices, like whether or not to start a family. 

References

National Institute of Diabetes and Diabetes and Digestive and Kidney DIseases2022). Kleine-Levin Syndrome. Retrieved December 19, 2022, from https://www.niddk.nih.gov/health-information/kidney-disease/children/kidney-dysplasia#whatis

Cleveland Clinic (2022). Joubert Syndrome Retrieved December 19, 2022, https://my.clevelandclinic.org/health/articles/6040-joubert-syndrome