Alexander Disease

By Kristen Pruett

What is Alexander Disease?

Definitions You Need to Know:

Leukodystrophy: refers to progressive degeneration of the white matter of the brain due to imperfect growth or development of the myelin sheath.

Alexander disease: a rare disorder of the nervous system. It is one of a group of disorders, called leukodystrophies, that involve the destruction of myelin.

Myelin Sheath: the fatty covering that insulates nerve fibers and promotes the rapid transmission of nerve impulses.



Alexander Disease is a rare and usually fatal disease that is one of a group of neurological conditions known as the leukodysrophy. There are three forms of this disease: infantile, juvenile, and adult. The infantile form is the most common and begins around the first two years of life. The juvenile stage is less common and has an onset of around age two to thirteen. Adult forms of this disease are the least common.

Life with Alexander Disease

Infantile Stage
  • usually have mental and physical development delays
  • do not have developmental milestones
  • have an abnormal increase in head size
  • seizures

Juvenile Stage

  • may have excessive vomiting
  • difficulty swallowing and speaking
  • poor coordination
  • loss of motor control

Adult Stage

  • mimics the symptoms of Parkinson's disease or multiple sclerosis

Origins and Developments of Alexander Disease

95% of Alexander disease cases are caused by a genetic mutation in the protein GFAP while the other 5% are unknown. The GFAP gene provides instructions for making a protein called glial fibrillary acidic protein. The alteration in the GFAP gene leads to the formation of Rosenthal fibers which impair cell functions. The abnormal gene can be passed down from a parent or be a new mutation in the individual, most are the latter.

How does Alexander Disease affect the brain?

What causes Alexander disease is the destruction of "white matter" in the brain. White matter is myelin, which protects the nerve fibers in the brain. Alexander disease are abnormalities in the myelin. Sometimes Rosenthal fibers form in the brain. These are clumps of proteins that form in non-neuronal cells of the brain called astrocytes.

Alexander Disease and the Brain

Frontal Lobe - This lobe is responsible for motor functions. Individuals with Alexander disease usually have poor motor control, therefore their frontal lobe is affected.


Temporal Lobe - This lobe is responsible for language. Many individuals with Alexander disease do not have developmental milestones, like speach.


Cerebellum - This lobe is responsible for coordination. The cerebellum of individuals with Alexander disease is affected because they typically have poor coordination


Brain stem - The brain stem's function is to control the autonomic functions in the body. Because individuals with Alexander disease sometimes have trouble with speaking and swallowing it means that the brain stem is affected by this disease.

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Diagnosis and Prognosis

Diagnosis

For many years the presence of Rosenthal fibers was required to be able to diagnose Alexander disease. However this can be ambiguous because it can be found in other disorders. More recently MRI criteria have been accurate and successful in diagnosing Alexander disease. Definitive diagnosis can be obtained through blood testing or swabbing of the cheek to test DNA.


Prognosis

Prognosis for people with Alexander disease is usually poor. Children with the infantile form of the disease do not usually live past 6 and children with the juvenile and adult forms typically have a slower, more lengthy course.

Treatments

There is no cure for Alexander disease and there is no standard course of treatment. Treatment is symptomatic and supportive and usually therapy and genetic counseling are beneficial for the patient and their family. Genetic counseling is helpful because it gives advice to prospective parents concerning the chances of genetic disorders in a future child. This can alleviate some of the anxiety a family could have from caring for a child with a disease like Alexander disease.

Research and Organizations

Research

As mentioned previously, most recent research has been discovered that individuals with Alexander disease have a mutation in the gene that makes GFAP. Scientists have not proven how the mutation causes the disease and are trying to understand this. Studies are also being done to find a possible treatment for the disease.


Organizations

Statistics

  • About 500 cases have been reported since the disorder was first described in 1949.

Video

info on alexanders disease

Leukodystrophy Awareness Month

Tuesday, Sep. 1st, 12am to Wednesday, Sep. 30th, 12am

Worldwide

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Works Cited

"Alexander Disease." NORD National Organization for Rare Disorders Alexander Disease Comments. N.p., n.d. Web. 02 June 2015. <http://rarediseases.org/rare-diseases/alexander-disease/>.


"Alexander Disease." United Leukodystrophy Foundation. N.p., n.d. Web. 02 June 2015. <http://ulf.org/alexander-disease>.


"NINDS Alexander Disease Information Page." United Leukodystrophy Foundation. N.p., n.d. Web. 02 June 2015. <http://www.ninds.nih.gov/disorders/alexander_disease/alexander_disease.htm>.