Symptoms
A comparison shot between a normal brain and an abnormally large brain (megalencephaly)Symptoms of Alexander Disease (AD) vary depending on the type of the disorder.
Infantile AD
- Developmental delay
- Seizures
- Megalencephaly (Enlarged brain size)
- Difficulty in swallowing, talking or eating
- Difficulty in co-ordination including activities such as walking or movement in general
- Double Vision
- Vomiting
- Hemiparesis (progressive weakening of a single side of the body)
- Intellectual disability
- Sleep apnea (difficulty in breathing while asleep)
- Spastic quadriparesis (the weakening of all four limbs)
- Hydrocephalus (a condition where excessive quantities of fluid buildup in the skull results in the swelling of the brain)
As it can be easily seen from above, the major symptoms may often lead to fatal consequences to an infantile and thus, the average life expectancy of a patient suffering from AD is usually low. (4)
Juvenile & Adult AD
- Speech and swallowing difficulties
- Seizures
- Ataxia (poor co-ordination)
- Progressive intellectual decline
- Breathing problems
- Chronic stress
- Similar symptoms from Infantile form
The major difference between the symptoms existent in the Infantile form, Juvenile form and Adult form is the progressive speed of the symptoms. Generally speaking, the Infantile form has the fastest progressive deterioration and the more severe symptoms, whilst the Juvenile form and Adult form may experience a slower deterioration. Some patients diagnosed with Adult AD may not even suffer from the deterioration of myelin due to the extreme slow nature of the deterioration, and thus may live a relatively normal life. (4, 15)
Infantile AD
- Developmental delay
- Seizures
- Megalencephaly (Enlarged brain size)
- Difficulty in swallowing, talking or eating
- Difficulty in co-ordination including activities such as walking or movement in general
- Double Vision
- Vomiting
- Hemiparesis (progressive weakening of a single side of the body)
- Intellectual disability
- Sleep apnea (difficulty in breathing while asleep)
- Spastic quadriparesis (the weakening of all four limbs)
- Hydrocephalus (a condition where excessive quantities of fluid buildup in the skull results in the swelling of the brain)
As it can be easily seen from above, the major symptoms may often lead to fatal consequences to an infantile and thus, the average life expectancy of a patient suffering from AD is usually low. (4)
Juvenile & Adult AD
- Speech and swallowing difficulties
- Seizures
- Ataxia (poor co-ordination)
- Progressive intellectual decline
- Breathing problems
- Chronic stress
- Similar symptoms from Infantile form
The major difference between the symptoms existent in the Infantile form, Juvenile form and Adult form is the progressive speed of the symptoms. Generally speaking, the Infantile form has the fastest progressive deterioration and the more severe symptoms, whilst the Juvenile form and Adult form may experience a slower deterioration. Some patients diagnosed with Adult AD may not even suffer from the deterioration of myelin due to the extreme slow nature of the deterioration, and thus may live a relatively normal life. (4, 15)
Causes
Alexander Disease results from a mutation in a gene within chromosome 17 known as the *Glial Fibrillary Acidic Protein (GFAP) gene. Typically, this mutation will occur randomly including individuals with no history of the disease in their family. The reason behind the mutation is yet to be known. However, there have been reported cases of AD without GFAP gene mutations, giving scientists a possibility that there may be an unknown factor behind the cause of AD. Inheriting the disorder is also a possibility in patients. If a patient survives AD until they are an adult or if the patient is suffers from the Adult form of AD, and the patient wishes to have an offspring, it is important that the patient is aware of the fact that the patient with the defective gene has a 50% chance of passing it onto the next generation. For these reasons, it is extremely rare to find a family with more than a single generation of AD. (4,5)
*First characterized and named in 1969 by Lawrence F. Eng, the GFAP gene contains information for creating the GFAP. Simply put, the GFAP provide strength and support to cells and also contribute towards the recovery of the brain or spinal cord if they are injured. Some researchers also have speculated that the GFAP may be involved in the production and maintenance of the white matter in the brain (myelin). (8)
*First characterized and named in 1969 by Lawrence F. Eng, the GFAP gene contains information for creating the GFAP. Simply put, the GFAP provide strength and support to cells and also contribute towards the recovery of the brain or spinal cord if they are injured. Some researchers also have speculated that the GFAP may be involved in the production and maintenance of the white matter in the brain (myelin). (8)