Canavan Disease

Canavan disease is a progressive, fatal, genetic disorder affecting the central nervous system, muscles, and eyes. Early symptoms in infancy may include increased head size, weakness, low muscle tone and loss of head control. Symptoms progress to seizures, blindness, inability to move voluntarily and difficulty eating solids or swallowing liquids. This condition is caused by changes in the ASPA gene and is inherited in an autosomal recessive pattern. Canavan disease is diagnosed based on symptoms, laboratory testing, and genetic testing.

Genetic Mutations: Canavan disease is caused by genetic mutations, also known as pathogenic variants. Genetic mutations can be hereditary, when parents pass them down to their children, or they may occur randomly when cells are dividing. Genetic mutations may also result from contracted viruses, environmental factors, such as UV radiation from sunlight exposure, or a combination of any of these.

If you suspect you may have this disease, you may want to start collecting your family health history. Information such as other family members who have had similar symptoms, when their/your symptoms first appeared, or exposures to any potential disease-causing environmental factors should be discussed with your medical team.

Disruption Metabolism: Canavan disease is caused by a disruption in a person’s metabolism. Metabolism is the series of chemical reactions in our body that turns the food we eat into energy and removes toxins. Hormones and specific proteins, called enzymes, help make the right chemical reactions happen in the right order. However, genetic changes can prevent hormones or enzymes from working properly, which can lead to a disruption in metabolism such as energy not being created for the body or toxins not being removed from the body.

Damaged White Matter in CNS: Canavan disease is caused by damaged white matter in the central nervous system (CNS). The brain and spinal cord make up the CNS. The white matter portions of the CNS get its color from a tissue called myelin. Myelin is made up of proteins and fatty materials called lipids. Myelin wraps around nerves, protecting them and helping to speed up the signals between nerves in the CNS. Genetic changes can affect the growth or function of myelin, which can slow or block the communication between nerves.

Yes. It is possible for a biological parent to pass down genetic mutations that cause or increase the chances of getting this disease to their child. This is known as inheritance. Knowing whether other family members have previously had this disease, also known as family health history, can be very important information for your medical team.

There are multiple ways, or patterns, a disease can be inherited depending on the gene(s) involved. Based on GARD’s current data, this disease can be inherited in the following pattern(s):

Autosomal Recessive: Autosomal means the gene involved is located on one of the numbered chromosomes. Recessive means that a child must inherit two copies of the mutated gene, one from each biological parent, to be affected by the disease. A carrier is a person who only has one copy of the genetic mutation. A carrier usually doesn’t show any symptoms of the disease.

If both biological parents are carriers, there is a 25% chance their child inherits both copies of the mutated gene and is affected by the disease. Additionally, there is a 50% chance their child inherits only one copy of the mutated gene and is a carrier.