Beginning in infancy, Canavan disease [CD] is a neurological disorder that is both progressive and fatal. It is caused when there is a genetic abnormality present which causes a deterioration of the white matter in the brain. In turn, this prevents the nerves from receiving the proper signals from the brain as to what should be done.
Important Statistics on Canavan Disease
1. It is estimated that 1 in 40 Ashkenazi Jews is a carrier of the Canavan gene, but it can also be found in other ethnic groups.
2. The number of Jews who have Canavan disease right now: 1 in 5,000.
3. Studies suggest that this disorder affects 1 in 6,400 to 13,500 people in the Ashkenazi Jewish population.
4. Most of the children born with Canavan disease today have no known Jewish heritage because of advanced genetic screening. Genetic testing can identify about 97% of Ashkenazi Jewish carriers.
5. Outside of the Ashkenazi Jewish population, the ethnic group that is believed to be most at risk for the development of CD is the Saudi Arabian general population.
6. When both parents are a carrier of CD, there is a 1 in 4 chance in every pregnancy that the child born with have the disease.
7. 50%. That’s the chances that a child will become a carrier of CD when both parents are carriers of the gene.
8. Mutations in the ASPA gene cause Canavan disease. A diagnosis may be made before the baby is born [a prenatal diagnosis] by testing the amniotic fluid.
9. Canavan disease was first described in 1931 by Myrtelle Canavan.
10. Death usually occurs before age 4, but some children with milder forms of the disease survive into their teens and twenties.
11. Gene therapy experiments in 2012 have shown life improvements in patients without long-term adverse effects at the 5 year follow-up mark.
12. Research involving triacetin supplementation has shown promise in a rat model.
13. Brain gene therapy at Cooper University Hospital, through the use of 6 inserted catheters and billions of engineered virus particles, has been shown to have the potential of reversing the effects of CD.
14. While Canavan does occur in other ethnic groups, it is rare and carrier frequency in the non-Jewish population has not yet been measured.
15. The common pan-European mutation, A305E, was identified in 40% of the alleles and the overall detection rate was 93%.
16. Canavan disease is caused by a deficiency of an enzyme, aspartoacylase. Without the enzyme, the myelin sheaths cannot be properly maintained.
Causes and Symptoms
The symptoms of Canavan disease vary from person to person based on the severity of the condition. Most children who have this disease have a head circumference that rapidly increases while they exhibit a lack of overall head control. Children will also have reduced vision and may exhibit changes in muscle tone that can be either very stiff or virtually useless. Because of this, it is extremely rare for children with CD to be able to walk, crawl, talk, or even sit.
The symptoms of Canavan disease typically become apparent by the 9th month of age. It can be seen as early as 3 months. Most children who have this disease will typically die from it before they reach their 10th birthday. There is no cure for CD and no effective treatment plan that can help to prolong life. As the disease progresses, children may have seizures, suffer from paralysis develop blindness, and even have difficulty in swallowing. Treatment options are responsive instead of proactive and are designed to help give a child comfort.
With extensive screening processes being developed, it is possible to find out who the carriers of this disease happen to be so that there is no possibility of it being sent down to future generations. As the statistics show, we may still have a long way to go in order to stop this disease from filtering down.
Treatment and Prevention
The good news is that there are many treatment options on the horizon for Canavan disease. The bad news is that those treatments might not be available for children born today with it. Many trials are close to showing long-term successes, but they just aren’t there quite yet. With children often dying before the age of 4 when they have this disease, there is very little room for maneuverability. One day children may be effectively treated, but that day is not today.
That means children today are typically treated based on the symptoms that are being displayed. They might be given braces for muscle and joint support. Being given oxygen to help with breathing may also occur. The best course of action is to begin tracking statistics in other ethnic groups so that the true nature of this disease can be tracked. Genetic testing is only recommended right now if both parents come from the specific Jewish ancestry that has high prevalence rates of this disorder. By having widespread testing, discovering CD doesn’t have to be a guessing game.
Some people may be hesitant to attempt gene therapy with some of its failures over the years, including a well publicized death that occurred in Philadelphia in 1998, but the reality is that children and parents who are dealing with CD have very few choices. The biggest fear isn’t that a therapy will fail. It is that it just won’t be effective enough.
Outside of gene therapy, even direct injections of the missing enzyme into the blood stream of children with Canavan disease have been found to be beneficial. As more is learned about this disease, the better off we will be able to respond to it, test for it, and prevent childhood fatalities. More research needs to be done, which means your help is needed. Share these statistics so that everyone can get involved in the fight to end childhood genetic diseases today.