Ataxia Telangiectasia

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Ataxia Telangiectasia is an acute neurodegenerative disorder that leads to various health complications in sufferers. Know what is Ataxia Telangiectasia and read about its causes, symptoms, diagnosis and treatment.

Ataxia Telangiectasia Definition

It is a rare childhood syndrome that affects various organs of the human body, especially the brain. A primary immunodeficiency condition, it gives rise to acute disability in patients.

It is known by many other names, such as:

  • A-T
  • ATM
  • Boder-Sedgwick syndrome
  • Louis-Bar syndrome

The name of the condition is a merger of two different terms – “Ataxia” which refers to uncoordinated movements like walking and “Telangiectasia” which stands for the enlarged blood capillaries (vessels) immediately underneath the surface of the skin. Telangiectasias look like red, small spider-like veins.

Ataxia Telangiectasia ICD 9 Code

The ICD 9 Code for this syndrome is 334.8.

Ataxia Telangiectasia Pronunciation

The condition is pronounced in English as “At-uck-seah tay-lan-giak-tasia”.

Ataxia Telangiectasia Incidence

Ataxia Telangiectasia Syndrome affects 1 in 40,000 to 100,000 people of the world population. A-T has not been found to show preference for any particular race or geographic location. This disorder affects both males and females at an equal rate.

Many children with A-T are supposed to die at a very young age, even before they are properly diagnosed. Due to this reason, the condition is supposed to have a greater prevalence than is projected.

Ataxia Telangiectasia Types

A-T is often classified into different types. These are:

Type I A-T

It is a classic case of the condition where patients exhibit most or all of the diagnostic symptoms.

Type II A-T

In this form, patients do not suffer from all the usual clinical findings. However, they may show sensitivity to radiation therapy.

Type III A-T

In this type, patients display all the classic diagnostic symptoms but do not exhibit sensitivity to radiation.

Type IV A-T

In this stage, sufferers only exhibit some clinical features of this syndrome and are not sensitive to radiation.

Ataxia Telangiectasia Symptoms

The disease impacts the cerebellum of the brain, which controls the motor coordination of the body. It is also found to weaken the immune system in approximately 70% patients, thus causing respiratory disorders and heightening the risk of cancer.

The syndrome first manifests itself in early childhood. It is first exhibited in toddlers through signs and symptoms like:

  • Poor balance
  • Slurred speech
  • Reduce coordination of movements (Ataxia) during late childhood
  • Delayed walking
  • Jerky, unsteady gait
  • Increased vulnerability to infections
  • Delayed development of motor skills, which stops or retards after 10-12 years of age
  • Discoloration of patches of skin exposed to sunlight

These typically appear within the first decade of the life of a patient. In the later stages of the disease, patients may suffer from other abnormal symptoms, mainly including the development of Telangiectasias. These are small, red “spider-shaped” veins that appear on the skin of the ears, nose and cheeks or inner side of the knee and elbow. In many patients, these enlarged veins become prominent in the corners of the eyes. They also arise on other sun-exposed regions of the skin, such as the conjunctiva (mucous membranes of the eyes) and some areas of the extremities.

These are characteristic symptoms of A-T, which are not always present and generally do not appear in the first years of life.

Some other later symptoms include:

  • Seizures
  • Premature graying of the scalp hair
  • Abnormal or jerky eye movements (Nystagmus)
  • Inflammation of blood capillaries in the whites of the eyes
  • Acute, recurring respiratory infections
  • Sensitivity to radiation, including X-ray tests

Individuals affected by this condition tend to have elevated levels of a protein, known as alpha-fetoprotein (AFP), in their bloodstream. Elevated levels of this protein are usually found in the bloodstream of pregnant women. It is not known why and how A-T causes an abnormal increase of this protein in affected people.

Fortunately, children suffering from A-T do not usually exhibit mental difficulties. The level of intelligence is found to be normal or above normal in most of them.

Ataxia Telangiectasia Causes

A-T is supposed to result from mutations in the ATM gene, which is responsible for encoding a kinase essential for p53 activity. It is involved with detecting and correcting faults in DNA duplication at the time of cell division and destroying the cells when it is unable to correct the defects. Generally, the protein repairs double-stranded DNA breaks.

This gene also plays an essential role in the normal growth and activity of various body systems, such as the immune system and nervous system.

When mutations occur in the ATM gene, its function gets reduced or even eliminated. In the absence of this protein, cells may get unstable or even die prematurely. Cells located in the cerebellum of the brain are particularly affected due to this mutation. It is the cerebellum which coordinates movements of the human body. Naturally, an absence of these cells results in problems in movements, characteristic of A-T. Genetic mutation also prevents cells from showing proper response to DNA damage. This allows accumulation of breaks in DNA strands which may also lead to the development of cancerous tumors.

Is Ataxia Telangiectasia Inherited?

This is an autosomal recessive disease, meaning the genetic defect (causative of this condition) is inherited from both parents. An individual can acquire this disease only when both of his or her parents carry a copy of the mutated ATM gene. However, many individuals with both parents carrying the genetic defect are not found to exhibit any signs and symptoms of the disorder.

Ataxia Telangiectasia Carriers

In genetics, the word “carrier” refers to any person who has one normal as well as one mutated copy of a gene which is associated with some particular disorder. Generally, such individuals have very mild or almost no symptoms of the disease. Due to this reason, they are not aware of being carriers of the condition. A person can be said to be an A-T carrier if he or she possesses one normal and one mutated copy of the ATM gene.

60% of individuals within 70 years of age are supposed to be carriers of mutated ATM genes. Mutated ATM carriers are at a 16 times higher risk of breast cancer then that of normal individuals. On an average, such individuals die 7–8 years earlier than healthy individuals. Heart disease is often found to be the cause of this problem.

Ataxia Telangiectasia in USA

Approximately 1 percent of the US population is estimated to carry one normal as well as one mutated copy of the ATM protein in each cell. Approximately 2.5 million people or about one percent of the U.S. population are supposed to be the carriers of this disease.

Ataxia Telangiectasia Diagnosis

The condition is generally diagnosed when a child suffering from ataxia (inability to coordinate voluntary muscular movements) develops Telangiectasia. As aforesaid, Telangiectasia are the small red veins that arise at the corners of the eyes and sometimes also on the nose and the cheeks. If doctors suspect A-T due to observation of Telangiectasia, they can also look for other physical signs like:

  • Reduced physical development
  • Mask-like appearance of face
  • Reduced or absent deep tendon reflexes
  • Retarded or absent sexual development
  • Undersized spleen, lymph nodes and tonsils
  • Multiple changes in skin color and texture

Some possible diagnostic exams for the disease include:

  • Glucose tolerance test
  • Alpha fetoprotein
  • Carcinoembryonic antigen
  • B and T cell screen
  • Serum immunoglobulin levels (IgA, IgE)
  • Genetic testing, to detect mutations in the ATM gene
  • X-rays, to evaluate the size of the thymus gland

Ataxia Telangiectasia Differential Diagnosis

While diagnosing A-T, physicians may consider differentiating it from several other disorders that produce similar symptoms. These include:

Ataxia Telangiectasia Treatment

Unfortunately, there is still no cure for this disorder. Treatment for the condition is basically symptomatic and fails to address its actual cause. Doctors may consider administering affected children with gamma-globulin shots or extra doses of vitamins to boost their immunity. A strong immune system may help patients get rid of many of the problems resulting from this ailment. If patients develop cancer, parents can subject them to chemotherapy or leave them as it is. This is because patients with A-T generally have a low immunity and it may worsen when radiation or chemotherapy is used. Ideally, sufferers of this condition should never be given radiation therapy as they are very sensitive to radiation. Even X-ray examinations should not be conducted unnecessarily. When cultured in the laboratory, the skin and blood cells of A-T sufferers are found to have extremely decreased ability to replicate and make cell colonies after exposure to X-ray. The sensitivity of cells to X-ray was found to be greater than those of the general public.

Occupational and Physical therapy may help patients maintain the flexibility of their body. Speech therapy may also be required.

Ataxia Telangiectasia Prognosis

The prognosis for this disease is poor. Many patients with A-T develop chronic lung infections due to a weakened immune system. They are also highly susceptible to cancerous conditions. A-T sufferers are especially vulnerable to cancer of immune system cells (Lymphoma) and cancer of blood-manufacturing cells (Leukemia).

Ataxia Telangiectasia Life Expectancy

In case of A-T, life expectancy is found to vary from person to person. Generally, people with this condition survive into adulthood. However, life expectancy is often found to be reduced. Early death is common in sufferers of this syndrome. A sizeable percentage of A-T sufferers are found to die in their teen years or ealy-20s.

Ataxia Telangiectasia Complications

Individuals carrying mutated ATM genes are extremely susceptible to malignant conditions, such as Breast cancer, Lymphoma and Leukemia. They are also at an increased risk of suffering from disorders like:

  • Diabetes
  • Scoliosis
  • Kyphosis
  • Heart disease
  • Recurrent acute lung infections
  • Progressive movement disorder, which makes patients wheelchair-bound in later stages

Ataxia Telangiectasia Prevention

Unfortunately, the disorder is still not preventable in any way. Couples who are considering pregnancy and have a family history of this disorder may benefit from genetic counseling. Parents of a child with this condition may have a moderately increased risk of cancer and should consider more intensive cancer screenings as well as genetic counseling. Individuals with a family history of A-T should use genetic counseling before having children to check whether their partners are also acting as carriers of the recessive gene (causative of this condition). Heterozygote family members are also recommended to be regularly monitored for cancers.

Ataxia Telangiectasia Foundation

It is a non-profit organization that finances medical research on finding a cure for A-T. The registered address of this establishment is:

Ataxia Telangiectasia (A-T) Medical Research Foundation

16224 Elisa Place

Encino, CA  91436.

The organization can be contacted at:

Tel: 818-906-2861

Fax: 818-906-2870

Email: [email protected].

Ataxia Telangiectasia Organizations

Apart from A-T Medical Research Foundation, many other organizations associated to this disease have originated in recent times. Many of these fund and promote medical research on the disorder, raise awareness about the condition and assist A-T sufferers as well as their families with information.

If you find any child in your family exhibiting the symptoms of this disorder, call for an appointment with your health care provider. Even though the condition cannot be cured, medical care may help manage it more effectively and ensure greater comfort for the patient.

References:

http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002369/

http://emedicine.medscape.com/article/1113394-overview

http://www.cancer.gov/cancertopics/factsheet/Risk/ataxia

http://www.umm.edu/ency/article/001394.htm

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