What Is Canavan Disease?
Canavan disease is a genetic disorder in which the nerve cells or neurons present in the brain are unable to send and receive information effectively. It is one of a series of genetic disorders known as leukodystrophies, although, unlike most leukodystrophies, it is not fatal. The brain degenerates into spongy tissue studded with small fluid-filled holes in Canavan disease.
According to new research that has surfaced, the brain cells responsible for producing myelin sheaths, known as oligodendrocytes, cannot perform this crucial developmental activity. Myelin sheaths are fatty coverings that act as insulators and nutritional support for nerve cells around nerve fibers in the brain. Many oligodendrocytes do not mature and instead die in Canavan disease, leaving nerve cell projections known as axons susceptible and unable to function properly.
Although children of any ethnic origin can be affected by this fatal neurological illness, it is more common among Ashkenazi Jews. Canavan illness is far less common in the general population, though no one knows for sure. Children with Canavan illness may not show any signs at all when they are born. Within a few months, symptoms of the illness usually arise. Canavan disease in its juvenile form is less common. Beginning in childhood, affected individuals experience somewhat delayed speech development and motor skills. Canavan disease can produce delays that are so minor and generic that they are never detected as such. People with Canavan illness have a variable life expectancy. The neonatal type affects the majority of people till they reach childhood, while some may live into adolescence or even beyond. The mild or juvenile form does not appear to be associated with a shorter lifetime.
What Is the Cause Behind Canavan Disease?
Canavan disease is associated with mutations in the ASPA gene. The ASPA gene directs the production of an enzyme known as aspartoacylase. This enzyme ordinarily degrades a substance called N-acetyl-L-aspartic acid (NAA), which is found mostly in brain neurons. New research suggests that it is possible that the enzyme is involved in the transportation of molecules of water out of neurons. Aspartoacylase is inhibited due to mutations in the ASPA gene, which hinders the normal breakdown of NAA. The mutations that cause the neonatal or infantile type of Canavan syndrome substantially reduce the enzyme's activity, causing NAA levels in the brain to rise to dangerously high levels. The mutations that cause the disorder's mild or juvenile variant have a weaker influence on the enzyme's function, resulting in less NAA buildup. The signs and symptoms of Canavan illness are linked to an excess of NAA in the brain. According to studies, if NAA is not effectively broken down, the resulting chemical imbalance disrupts the production of the myelin sheath as the nervous system develops. The accumulation of NAA also causes the breakdown of existing myelin sheaths. Nerves that lack this protective covering malfunction, causes brain growth to be disrupted.
What Are the Symptoms of Canavan Disease?
The disease's symptoms can be extremely varied. Children with the condition may or may not experience the same symptoms. The following are some of the most typical symptoms observed:
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A bigger than average head circumference.
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Decreased visual response and abnormal muscular tone, resulting in stiffness or floppiness.
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While chewing the food, it occasionally streams up the nose.
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Insomnia.
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Issues with the control of the neck and head.
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Odd posture observed with legs frequently kept straight and arms flexed.
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Seizures are also observed.
The increase in head size usually happens all of a sudden. Other symptoms take longer to appear. As a baby's development slows, visual impairments, for example, may become more apparent. Canavan disease is a progressive disorder, which means that the symptoms will get worse with time.
How Is Canavan Disease Diagnosed?
Infants exhibiting the symptoms of Canavan disease can be suspected of having the disease, for example, macrocephaly, poor head control, etc.
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A thorough clinical evaluation, a full medical history of the patient, and a variety of specialist testing can all help to confirm the diagnosis.
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Gas chromatography-mass spectrometry, a device that may identify increased amounts of NAA in the urine, is one of the diagnostic tools. NAA levels are also elevated in the blood and cerebrospinal fluid (CSF). The deficiency of the enzyme aspartoacylase can be detected in some connective tissue cells from the skin.
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Amniocentesis measures the activity of the aspartoacylase enzyme, which measures the level of NAA in the amniotic fluid that surrounds the growing baby during 16 weeks to 18 weeks of gestation. It can be used to diagnose Canavan disease prenatally. If both parents have known ASPA gene mutations, prenatal diagnosis is possible through chorionic villus sampling (CVS), which involves taking a sample of placental cells at 10 weeks to12 weeks of pregnancy and analyzing it for mutations.
What Is the Treatment for Canavan Disease?
Canavan illness has no known cure. The goal of the treatment is to improve the child's quality of life while reducing their symptoms. The treatment regimen for a child will differ depending on their specific symptoms. The child's pediatrician will collaborate with the parents and the child to identify the best way to satisfy their requirements.
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Feeding tubes, for example, can be beneficial for children who have severe swallowing difficulties. These tubes can help the child get all of the nutrition he or she requires, as well as enough fluids to stay hydrated.
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Physical therapy and adaptive equipment can help them improve their posture. Controlling seizures with lithium or other drugs may be beneficial.
Conclusion:
In addition to the growing body of medical knowledge on Canavan disease, parent and family community support has grown. Canavan disease patients can also benefit from forums or support groups. Because of advancements in comprehensive care, the prognosis for childhood Canavan disease has gradually improved. Future studies will potentially aid in the development of safe and effective treatment for Canavan disease patients, thereby improving their quality of life. Their pediatrician delivers the finest source of information on a child's condition. Their prognosis varies depending on the severity of the illness, its symptoms, and any complications that arise.
Many children with Canavan illness suffer difficulties as a result of central nervous system problems. It has a mild type that causes developmental delays. Children with the mild form of Canavan disease can often live well into adulthood, despite the fact that it is less common than other types of the condition.
