Canavan Disease - Symptoms, Causes and Treatment
Canavan disease is a genetic disorder caused due to mutation in gene that helps in production of Aspartoacylase enzyme.
What is Canavan disease?
Canavan disease (also known as ASPA deficiency, ACY2 deficiency or Aspartoacylase deficiency) as described and studied by Myrtelle Canavan, is a common degenerative disease which occurs during infancy. It is a neurological genetic disorder inherited by infants from their parents carrying mutated genes, and is also known as leukodystrophies and linked to mutation in the gene encoding for missing aspartoacylase enzyme. The gene causing this disorder is located on chromosome 17.
This disease is characterized by degeneration of white matter of brain into spongy tissue and improper development of a protective covering named myelin sheath around nerve fibers in the brain and fluid.
Symptoms
The syndromes of this disorder start showing during early infancy and keep growing rapidly after that. The symptoms include flexion of arms and hyperextension of legs, atonia of neck muscles (abnormal development of muscles leading to floppiness or stiffness in muscles), hypotonia, eyesight related problems that sometimes lead to complete blindness, mental health related problems such as mental retardation, difficulty involved with the motor movements and feeding, hearing loss, problem in balancing the head due to an abnormally big head (known as megalocephaly) and in some cases paralysis.
Causes
As mentioned earlier, this disease is a genetically inherited disorder mainly caused due to autosomal recession and defect/mutation in the aspartoacylase enzyme producing gene ASPA located on chromosome 17 in humans. The enzyme plays an important role of breaking down N-acetyl aspartate (a brain molecule), which when decreased can lead to a condition where excess of N-acetyl aspartate molecules causes damage to myelin sheath by interfering with the growth of the sheath that covers the nerve fibers. Due to hindered growth of the sheath, transmission of nerve impulses that are sent through the nerve fibers are affected causing other complications.
Although this disorder can occur in people irrespective of which geographical region they live, it is found that people of Eastern European ancestry and from western Russia and Saudi Arabia are more prone to this disorder.
Diagnosis and Treatment
Prenatal testing such as genetic testing and blood test are done to diagnose this disorder. If both the parents are the carriers of the mutated genes, genetic counseling is suggested in such cases. DNA linkage analysis is (DNA testing) is also used to find out if the fetus is infected with the disorder.
Post natal diagnostic tests used are medical imaging, genetic testing and blood test of the infant. Another method involves measurement of NAA levels in amniotic fluid.
Unfortunately till the date, there is no known cure for this disorder. However, research is being carried out across the world to help patients suffering from this disorder.
Symptomatic treatment and other approaches such as gene therapy (in this type of treatment, artificial/functional ASPA genes or neuronal stem cells are introduced in the child's brain to help increase the production of aspartoacylase enzyme). Physical and occupational therapies (such as massage and other approaches to help in training motor movements and other physical conditions caused by the disorder) etc. are used to help patients suffering from this disorder.
Canavan disease (also known as ASPA deficiency, ACY2 deficiency or Aspartoacylase deficiency) as described and studied by Myrtelle Canavan, is a common degenerative disease which occurs during infancy. It is a neurological genetic disorder inherited by infants from their parents carrying mutated genes, and is also known as leukodystrophies and linked to mutation in the gene encoding for missing aspartoacylase enzyme. The gene causing this disorder is located on chromosome 17.
This disease is characterized by degeneration of white matter of brain into spongy tissue and improper development of a protective covering named myelin sheath around nerve fibers in the brain and fluid.
Symptoms
The syndromes of this disorder start showing during early infancy and keep growing rapidly after that. The symptoms include flexion of arms and hyperextension of legs, atonia of neck muscles (abnormal development of muscles leading to floppiness or stiffness in muscles), hypotonia, eyesight related problems that sometimes lead to complete blindness, mental health related problems such as mental retardation, difficulty involved with the motor movements and feeding, hearing loss, problem in balancing the head due to an abnormally big head (known as megalocephaly) and in some cases paralysis.
Causes
As mentioned earlier, this disease is a genetically inherited disorder mainly caused due to autosomal recession and defect/mutation in the aspartoacylase enzyme producing gene ASPA located on chromosome 17 in humans. The enzyme plays an important role of breaking down N-acetyl aspartate (a brain molecule), which when decreased can lead to a condition where excess of N-acetyl aspartate molecules causes damage to myelin sheath by interfering with the growth of the sheath that covers the nerve fibers. Due to hindered growth of the sheath, transmission of nerve impulses that are sent through the nerve fibers are affected causing other complications.
Although this disorder can occur in people irrespective of which geographical region they live, it is found that people of Eastern European ancestry and from western Russia and Saudi Arabia are more prone to this disorder.
Diagnosis and Treatment
Prenatal testing such as genetic testing and blood test are done to diagnose this disorder. If both the parents are the carriers of the mutated genes, genetic counseling is suggested in such cases. DNA linkage analysis is (DNA testing) is also used to find out if the fetus is infected with the disorder.
Post natal diagnostic tests used are medical imaging, genetic testing and blood test of the infant. Another method involves measurement of NAA levels in amniotic fluid.
Unfortunately till the date, there is no known cure for this disorder. However, research is being carried out across the world to help patients suffering from this disorder.
Symptomatic treatment and other approaches such as gene therapy (in this type of treatment, artificial/functional ASPA genes or neuronal stem cells are introduced in the child's brain to help increase the production of aspartoacylase enzyme). Physical and occupational therapies (such as massage and other approaches to help in training motor movements and other physical conditions caused by the disorder) etc. are used to help patients suffering from this disorder.
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