Joubert Syndrome

 Joubert Syndrome

Overview

Joubert syndrome is a rare genetic disorder that happens when the part of a fetus’s brain doesn’t develop as it should. The syndrome has many subtypes that cause different symptoms, but it typically causes issues with muscle control or muscle tone, breathing and eye movement.

Each year, 1 in 100,000 babies worldwide are born with Joubert syndrome. Most children with Joubert syndrome inherit genetic mutations that cause it, but it can also happen sporadically (for no known reason)

Symptoms

Joubert syndrome causes different conditions and may change as children grow up. Symptoms may include physical differences, including facial differences, symptoms of certain eye conditions, and liver and kidney disease.

Your child may have the following neurological issues or conditions:

Hypotonia (decreased muscle tone) that becomes ataxia (issues with muscle coordination).

Eye conditions like nystagmus or strabismus (crossed eyes).

Breathing issues like tachypnea (fast, shallow breathing) or apnea (breathing that pauses).

Developmental delay.

Intellectual disability.

Physical differences

Your child may have the following issues or symptoms:

Cleft lip and palate.

Distinctive facial features like a broad forehead, droopy eyelids (ptosis) or eyes that are spaced wider than usual. Their ears may be set lower than usual, and their upper lip may turn up in the center so their mouths are shaped like a triangle.

Polydactyly (extra fingers and toes).

Protruding tongue.

Medical conditions

As they grow up, your child may develop medical conditions that affect their retinas (the part of your eye that converts light to images), kidneys and liver. For example, children may develop conditions like Leber’s congenital amaurosis, polycystic kidney disease or liver failure.

Causes

Joubert syndrome can be the result of mutations in more than 35 different genes that play a part in brain development. Most of the time, people inherit these mutations in an autosomal recessive manner, which means both biological parents pass on the genetic mutations that cause Joubert syndrome.

But one of these mutations is X-linked, meaning the change is on the X chromosome. Mutations on the X chromosome can pass in a dominant or recessive pattern, but not every pattern is clear on how a child acquires the mutation from their parents.

The genetic mutations that cause Joubert syndrome result in abnormal versions of your child’s cerebellum, brainstem and cilia:

The cerebellum manages coordination and movement. In Joubert syndrome, the cerebellar vermis is missing or is smaller than normal.

The brainstem, which regulates breathing and balance, doesn’t form correctly. When viewed on imaging scans, the abnormal cerebellar vermis and brainstem look like a molar tooth. Spotting that image, which healthcare providers may call molar tooth sign, is one way that they diagnose Joubert syndrome.

Cilia are tiny structures that stick out from cells’ surfaces, like antennas from the top of a building. Cilia on brain cells help them communicate with each other during organ development. Researchers believe mutations that affect cilia may cause eye, kidney and liver issues in people with Joubert syndrome.

These genetic mutations affect family members

That depends on factors like the type of genetic mutation and sex:

Autosomal recessive inheritance: Children with a biological sibling who has Joubert syndrome have a 25% chance of developing the condition, a 50% chance that they’ll carry the genetic mutation but not have symptoms, and a 25% chance that they won’t carry the mutation or have symptoms.

X-linked inheritance: Children assigned male at birth have a 50% chance of developing the condition. But if they don’t develop symptoms, they aren’t carriers. Children assigned female at birth have a 25% chance of developing the condition and a 50% chance that they won’t have symptoms but will carry the genetic mutation.

Diagnosis

Healthcare providers consider your child’s symptoms and imaging test results to diagnose Joubert syndrome. The criteria for diagnosing the condition are:

Molar tooth sign that’s visible on a brain MRI.

Hypotonia symptoms.

Development delay.

Providers may order genetic tests to confirm your child’s diagnosis and treatment. Studies show between 62% and 94% of children with Joubert syndrome have one of the genetic mutations that cause it. Identifying the specific mutation helps providers anticipate the kinds of health issues your child may have so they can treat them early on.

Treatment

Treatments are different for each child and depend on factors like the syndrome type and how it affects them. For example:

If your baby has breathing difficulties, they may receive breathing support like supplemental oxygen or mechanical ventilation.

Children of all ages with developmental delays may receive physical therapy, speech and language therapy and occupational therapy.

A child with strabismus (an eye condition) may have strabismus surgery.

Depending on the ways Joubert syndrome affects your child, you might need regular visits with specialists who’ll diagnose, monitor and treat issues like kidney disease, eye issues and neurological issues.

Type of Doctor Department :Neurosurgeons