Ataxia-Telangiectasia - Causes, Symptoms and Treatment

Introduction:

Ataxia-telangiectasia (A-T), also known as Louis-Bar syndrome, is a rare genetic disorder affecting the nervous system, immune system, and other body systems. Neurodegenerative disease occurs when cells in the body's central nervous system gradually stop working. The most common symptom of ataxia-telangiectasia is difficulty with movement and coordination (ataxia), which begins in childhood. In addition, small clusters of dilated blood vessels that appear in the eyes and on the skin are a distinguishing feature of telangiectasia.

Difference Between Ataxia and Apraxia:

• Apraxia: The brain is affected in this condition, making it difficult for the person to perform or describe everyday actions. It occurs due to the brain's difficulty in processing these actions.

• Ataxia: Ataxia is a condition that causes difficulties in coordinating muscle movements, affecting all actions. The brain has no trouble processing or describing tasks.

What Are the Types of Ataxia-Telangiectasia?

The three main types of ataxia are:

• Vestibular Ataxia: A problem with the inner ears that contributes to the sense of balance. It is challenging to coordinate one's movements with the balance being disrupted.

• Cerebellar Ataxia: Is caused by a problem in the cerebellum, a part of the brain that controls how different parts of the brain work together.

• Sensory Ataxia: The body has a built-in "self-positioning" sense that allows the brain to track the location of each body part. Sensory ataxia impairs the sense of self-positioning.

What Is Ataxia-Telangiectasia, and Whom Does It Affect?

A genetic mutation causes ataxia-telangiectasia. Anyone can inherit ataxia-telangiectasia if both parents have the gene mutation and pass it on to their child (autosomal recessive). Individuals can have one copy of the gene but do not show symptoms. Only an individual with two copies of the mutated gene can present with ataxia-telangiectasia. An estimated one percent of Americans have a mutated copy of the ataxia-telangiectasia mutated (ATM) gene. Ataxia-telangiectasia is uncommon, affecting approximately one in every 40,000 to 100,000 people worldwide.

What Are the Symptoms of Ataxia-Telangiectasia?

The symptoms of ataxia-telangiectasia are:

• Coordination issues.

• Walking unsteadily or with feet spread widely apart.

• Inadequate balance.

• Difficulty performing fine motor tasks like writing, eating, or buttoning a shirt.

• Speech modification.

• Involuntary eye movements back and forth.

• Swallowing difficulties.

What Are the Causes of Ataxia-Telangiectasia?

There are various types of ataxia, and there are numerous possible causes. The causes are classified as follows:

• Acquired: These are conditions and causes that have developed or affected one at some point. Some of these causes can be temporary and can be reversed.

• Inherited: These are genetic conditions, which means an individual has inherited them from one or both parents.

• Sporadic: These conditions are caused by spontaneous DNA (deoxyribonucleic acid) mutations that occur when a fetus develops in the uterus. These mutations do not come from either of the parents, and symptoms may appear in adults.

Other Conditions:

Ataxia can be caused by a variety of conditions or circumstances, including:

• Celiac disease.

• Alcohol intoxication.

• Brain tumors.

• Congenital disorders.

• Traumatic brain injuries.

• Degenerative brain disorders like Parkinson's disease.

• Stress.

• Fatigue.

• Drugs for depression and epilepsy.

• Genetic disorders like ataxia-telangiectasia, Friedreich's ataxia, Wilson's disease, and Niemann-Pick disease.

• Nutritional and vitamin deficiencies.

• Underactive thyroid gland.

• Exposure to toxic chemicals like mercury.

• Transient ischemic attacks.

• Stroke.

• Radiation sickness.

• Inflammatory and immune disorders.

• Infections.

How Is Ataxia-Telangiectasia Inherited?

Normally, each cell has two copies of a gene. One gene each from the mother and the father. A-T is inherited in an autosomal recessive pattern. A mutation must be present in both copies of the gene to be affected by autosomal recessive inheritance. A gene mutation must be passed down from both parents for a child to be affected. An individual is a carrier if only one copy of the gene mutation is present. When both parents carry a recessive gene mutation, a child has a 25 percent chance of inheriting two mutations and developing A-T. First-degree relatives, such as a person's parents, siblings, and children, have a 50 percent chance of having A-T. A prospective parent with gene mutation increases the risk of A-T and various cancers. There are options available for couples who want to have a child. Preimplantation genetic diagnosis (PGD) is a medical procedure performed in tandem with in-vitro fertilization (IVF). It enables couples with specific known genetic mutations to reduce the possibility for their children to inherit the condition. In a laboratory, the eggs are extracted and fertilized. When the embryos reach a certain size, a cell is removed and tested for the mentioned hereditary condition. The parents can then transfer non-mutated embryos to the woman's uterus. PGD has been in use for various purposes for over two decades.

How Is Ataxia-Telangiectasia Diagnosed?

The diagnosis of ataxia-telangiectasia includes a physical examination of symptoms followed by imaging and blood tests to confirm the genetic mutation responsible for symptoms in ataxia-telangiectasia. Before confirming the diagnosis, the healthcare provider gathers additional information about the child's health and family history through a thorough medical evaluation. In addition, people who have A-T should see an immunologist for a thorough workup and evaluation. The following tests help in diagnosing ataxia-telangiectasia:

• Genetic Testing: A blood test to identify the mutated gene mutation causing the symptoms.

• MRI (Magnetic Resonance Imaging): Imaging the brain to look for weakened neurons or cerebellar cells (cerebellar atrophy), a sign of progressive ataxia.

• Karyotyping: A blood test that looks for genetic conditions in chromosomes.

• Blood Tests: These are performed to look for elevated alpha-fetoprotein levels.

How Is Ataxia-Telangiectasia Treated?

The treatment of ataxia-telangiectasia depends on the symptoms of the condition. There is no known cure for A-T. Treatment differs for each individual diagnosed with the condition and may include the following:

• Avoiding excessive sun exposure to control dilated blood vessels (telangiectasia).

• Muscle strengthening exercises.

• Cancer chemotherapy treatment.

• Infections can be treated with antibiotics.

• Immunoglobulin therapy for the weakened immune system.

• Gamma globulin injections for respiratory infections.

Conclusion:

Ataxia-telangiectasia cannot be prevented as a genetic mutation causes it. However, one can reduce the chances of having a child with this genetic condition by not smoking and avoiding chemical exposure.