Joubert Syndrome
Description
Joubert Syndrome is a rare genetic disorder characterized by distinctive brain abnormalities, particularly affecting the cerebellum. This condition impacts motor skills, breathing, and cognitive abilities. Learn about the signs, symptoms, causes, diagnosis, management, and ways families can thrive despite the challenges of Joubert Syndrome.
Genes Involved
Genes Involved:
Joubert Syndrome is caused by mutations in various genes, including:
- AHI1
- TMEM216
- CEP290
- INPP5E
- C12orf65
- KIAA0586
- ARL13B
- RPGRIP1L
- OFD1
- NPHP1
- MKS1
- TTC21B
- BBS1
- BBS2
- BBS4
- BBS7
- BBS9
- BBS10
- BBS12
- These genes are involved in various cellular processes, including cilia formation, protein transport, and cell signaling.
Recognizing the Signs and Symptoms
Recognizing the Signs and Symptoms:
- Delayed motor development: This may include difficulty with sitting, crawling, walking, and coordination.
- Breathing problems: Individuals with Joubert Syndrome may have irregular breathing patterns, including pauses in breathing (apnea).
- Eye movement abnormalities: They may have problems with eye movements, such as nystagmus (rapid eye movements).
- Hypotonia (low muscle tone): This can make it difficult for infants to hold their head up or sit upright.
- Intellectual disability: The severity of intellectual disability varies widely, from mild to severe.
- Characteristic facial features: These may include a prominent forehead, a wide-set appearance, and a small chin.
- Molar tooth sign: This is a specific pattern of brain abnormalities seen on imaging studies.
- Other possible features: These can include seizures, hearing loss, and problems with speech and language.
Causes
Causes:
Joubert Syndrome is a genetic disorder, meaning it is caused by mutations in genes. These mutations are typically inherited from one or both parents, although some cases may occur spontaneously (de novo mutations).
Inheritance/recurrence risk
Inheritance or Recurrence Risk:
- Autosomal recessive inheritance: This means that both parents must carry a copy of the mutated gene for their child to have Joubert Syndrome. If both parents are carriers, there is a 25% chance with each pregnancy that their child will inherit the disorder.
- Autosomal dominant inheritance: In some cases, Joubert Syndrome is caused by a dominant gene mutation. This means that only one parent needs to carry the mutated gene for their child to have the disorder. In these cases, there is a 50% chance with each pregnancy that their child will inherit the disorder.
- De novo mutations: Occasionally, the mutated gene occurs spontaneously in the child, meaning it wasn‘t inherited from either parent. In these cases, the risk of recurrence in future pregnancies is low.
