TAR Syndrome
Description
TAR Syndrome, also known as Thrombocytopenia-Absent Radius Syndrome, is a rare genetic disorder characterized by the absence or malformation of the radius bone in the forearm, along with thrombocytopenia (low platelet count). This can lead to a variety of health challenges, including hearing loss, kidney abnormalities, and skeletal deformities. This blog will delve into the intricacies of TAR Syndrome, providing comprehensive information on its causes, symptoms, diagnosis, management, and resources for families.
Genes Involved
TAR Syndrome is caused by mutations in one of several genes, including:
- RBM8A: Mutations in this gene are the most common cause of TAR Syndrome.
- RMRP: Mutations in this gene can lead to a more severe form of TAR Syndrome.
- Other genes: Research continues to identify additional genes that may be involved.
Recognizing the Signs and Symptoms
Individuals with TAR Syndrome exhibit a range of symptoms, including:
- Absent or malformed radius bone: This results in a shortened forearm and an inability to fully extend the elbow.
- Thrombocytopenia: Low platelet count can cause easy bruising and bleeding.
- Hearing loss: Sensorineural hearing loss is common.
- Kidney abnormalities: These can range from minor to severe, impacting kidney function.
- Skeletal deformities: Other skeletal abnormalities may occur, such as abnormalities of the ribs, spine, and feet.
- Cardiac defects: In some cases, heart defects may be present.
- Facial features: Some individuals may have distinctive facial features, including a flattened nasal bridge and a small chin.
Causes
TAR Syndrome is caused by a genetic mutation, typically inherited in an autosomal dominant pattern. This means that a person only needs to inherit one copy of the mutated gene from a parent to develop the condition. However, in some cases, TAR Syndrome can occur due to a new mutation, meaning the mutation is not present in either parent‘s genes.
Inheritance/recurrence risk
If one parent has TAR Syndrome, there is a 50% chance that each child will inherit the condition. If both parents have TAR Syndrome, the chances of their child inheriting the condition are even higher. However, it‘s crucial to understand that genetic counseling can provide personalized insights into the likelihood of inheritance and recurrence risk.
