Ataxia - telangiectasiaLouis-Bar syndrome Is a rare childhood disease that affects the brain and other parts of the body. Ataxia refers to uncoordinated movements, such as walking. Telangiectasias are enlarged blood vessels (capillaries) just below the surface of the skin. Telangiectasias appear as tiny, red, spider-like veins.
Causes, incidence, and riskfactors Ataxia-telangiectasia is inherited, which means it is passed down through families. It is an autosomal recessive trait. This means that both parents must provide a defective gene for the child to have symptoms of the disorder. The disease results from defects in the ataxia telangiectasia mutated (ATM) gene. Defects in this gene can lead to abnormal cell death in various places of the body, including the part of the brain that helps coordinate movement. Boys and girls are equally affected.
Symptoms Decreased coordination of movements (ataxia) in late childhood Ataxic gait (cerebellar ataxia) Jerky gait Unsteady Decreasing mental development, slows or stops after age 10 - 12 Delayed walking Discoloration of skin areas exposed to sunlight Discoloration of skin (coffee-with-milk-colored spots) Enlarged blood vessels in skin of nose, ears, and inside of the elbow and knee Enlarged blood vessels in the whites of the eyes Jerky or abnormal eye movements (nystagmus) late in the disease Premature graying of the hair Seizures Sensitivity to radiation, including medical x-rays
Signs and tests The doctor will perform a physical exam. Examination may show signs of the following: Below normal sized tonsils, lymph nodes, and spleen Decreased to absent deep tendon reflexes Delayed or absent physical and sexual development Growth Failure Mask-like face Multiple skin coloring and texture changes
Possible tests include: Alpha fetoprotein B and T cell screen Carcinoembryonic antigen Genetic testing to look for mutations in the ATM gene Glucose tolerance test Serum immunoglobulin levels (IgE, IgA) X-rays to look at the size of the thymus gland
Expectations (prognosis) Early death is common, but life expectancy varies. Because persons with this condition are very sensitive to radiation, they should never be given radiation therapy, and no unnecessary x- rays should be done.
Complications Cancer such as lymphoma Diabetes Kyphosis Progressive movement disorder that leads to wheelchair use Scoliosis Severe, recurrent lung infections
Ataxia Telangiectasia OralEffects Ataxia telangiectasia is a rare childhood disorder. It causes damage in the part of the brain that controls movement and speech. People with this condition have: Ataxia -- difficulty controlling voluntary muscles Telangiectasias -- lesions of the skin or eyes Immune system malfunction The immune system problems are caused by abnormalities in two types of white blood cells — T cells and B cells. As a result, people with ataxia telangiectasia are more likely to get bacterial, fungal and viral infections.
Dental Correlation At the Dentist If you have ataxia telangiectasia, your dentist should make every effort to minimize the risk of infection. You will be given antibiotics before, during, and after the treatment. You will also be given antifungal medications before, during, and after your treatment as well. This will minimize the risk of infection and minimize the risk of spreading previous infections.
Classification In addition to the hallmark neurodegeneration, there are a number of other features that typify this debilitating disease. These include: immune dysfunction, sterility, radiosensitivity and lymphoid cancer. The immunodeficiency phenotype in AT is variable and usually manifests as decreased or absent IgA, IgE and IgG2.
•A major breakthrough in understanding AT came with the identification of a singlegene, ATM (ataxia telangiectasia, mutated), which when mutated is the underlying causeof the disease. ATM is essential for the repair of double-stranded breaks (DSB) in DNAwithout which abnormalities in regulation and cell growth occur:
The response in cells with normal ATM expression is initiated by histoneproteins which once activated recruit the MRN complex of proteins to thedamaged area. Autophosphorylation further drives the repair process:
Treatment There is no specific treatment for ataxia- telangiectasia. Treatment is directed at specific symptoms.
Prevention Couples with a family history of this condition who are considering pregnancy may consider genetic counseling. Parents of a child with this disorder may have a slight increased risk of cancer. They should have genetic counseling and more intensive cancer screenings.