More symptom information
Learn more about specific symptoms of this leukodystrophy in these pages.
Also known as: Hexosaminidase A (HEX A) deficiency; including some types of Tay-Sachs disease
GM2 gangliosidosis is a rare group of lysosomal storage disorders caused by mutations in the HEXA gene resulting in defective activity of enzymes involved in breaking down GM2 gangliosides. This results in a toxic build-up of them in the nerve cells of the brain and spinal cord leading to progressive neurological symptoms such as developmental regression, muscle weakness, and seizures. The two main types are Tay-Sachs disease and Sandhoff disease. Treatment focuses on managing symptoms and providing supportive care.
A new diagnosis can be overwhelming as it brings unique challenges and adjustments, but it is important to remember that you are not alone.
Mutations in the HEXA gene reduce its ability to produce an enzyme called beta-hexosaminidase A. This enzyme breaks down GM2 ganglioside. When this is not broken down, it builds up in nerve cells of the brain and spinal cord, causing the described symptoms.
Autosomal recessive: In autosomal recessive conditions, two copies of the genetic mutation are needed to cause the condition. We all have two copies of every gene, one from our mother and one from our father. The parents of someone with an autosomal recessive condition both carry one copy of the gene with a genetic mutation. Therefore, someone with an autosomal recessive condition has two copies of the genetic mutation, one copy from each parent. Each child of parents that both carry the genetic mutation will have a 25% chance of having the condition, a 50% chance of carrying the genetic mutation (like the parent), and a 25% chance of not having the condition.
Genetic counselling is essential for affected families due to the inheritance pattern of the condition. This is available at hospitals and Regional Genetic Centres. Please contact your doctor if you have any questions.
Learn more about genetic testing and counselling here.
Classic or infantile onset: symptoms typically first appear between three and five months of age. These may include feeding problems, general weakness (lethargy), and an exaggerated startle reflex in response to sudden loud noises. Motor delays and mental deterioration are progressive. A characteristic symptom of Tay Sachs disease, which occurs in 90 percent of cases, is the development of cherry red spots in the backs of the eyes. The infantile form often progresses rapidly, resulting in significant mental and physical deterioration.
Late-onset form: symptoms may become apparent anytime from adolescence through the mid-30s. Symptoms of late-onset Tay Sachs disease vary widely from case to case but can include loss of muscle coordination, muscle atrophy and weakness, and slurred speech. This disorder progresses much more slowly than the infantile form.
Learn more about specific symptoms of this leukodystrophy in these pages.
Although there is currently no specific treatment for this leukodystrophy, there is condition management information that may be useful for you in managing your or your loved one’s leukodystrophy.
There may be a current clinical trial, natural history study or patient registry for your condition. Check our current research page and ask your specialist doctor for more information.
We understand that research is a significant priority and source of hope for the leukodystrophy community. There is more research in leukodystrophy now than ever before. Alex TLC actively promotes and supports research in a number of ways.
Every month we update our database of research summaries with the most recent research. This includes summaries of leukodystrophy articles, clinical trials and pharmaceutical press releases. Our summaries allow our community to read about relevant recent research developments in a format that is easily understood.
Learn about the ways in which we can help in the how we support you section. When you or a family member been diagnosed with a leukodystrophy it may be difficult to know where to go for more advice – this information could help.
Our services and equipment section is here to help leukodystrophy patients and their families manage their condition. All information is based on our knowledge of UK services, however, our team are happy to receive support requests from other countries – email us.
You may be introduced to many different medical professionals which you may find confusing. View our guide to the health and care professionals you may encounter, with short descriptions about what they do.
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