Juvenile GM1 Gangliosidosis

What is juvenile GM1 gangliosidosis?

Juvenile GM1 gangliosidosis is a serious and progressive lysosomal storage disorder (disease) that destroys neurons (nerve cells) in the spinal cord and brain. It is important to look at the different types of GM1 gangliosidosis. The different types of GM1 gangliosidosis, which are all an inherited condition, can share similar symptoms and features. Although the types can also differ in varying degrees of severity, it is thought that juvenile GM1 gangliosidosis is typically caused by mutations within the specific GLB1 gene, which scientists believe is genetically passed on in an autosomal recessive manner. Juvenile GM1 gangliosidosis is a rare condition and is thought to affect approximately 1 in less than 200,000 people (newborns). While the frequency of Type l tends to be more highly reported than the other types, typically, people who have Type lll are associated with Japanese ancestry.

What are the symptoms of juvenile GM1 gangliosidosis?

Juvenile GM1 gangliosidosis can impact nearly every part of the body since the brain and spinal cord are affected as well as muscle and skeletal functions. The following are more specific symptoms based on type:

1. Classic infantile GM1 (Type l): Symptoms and signs of the most acute type of juvenile GM1 gangliosidosis (Type l) are usually visible near six years of age. While babies with type l may appear normal after birth, as the condition worsens, their development is impaired, and they fail to thrive. Developmentally, their muscles weaken. They may startle too easily after hearing common noises in their environment and experience impaired skeletal function as well as pain, stiffness, vision abnormalities (spots in the eyes that appear cherry-red), enlarged spleen and liver, cognitive disability, seizures, and an enlarged heart. Additionally, abnormal facial expressions can occur, as well as having gums that are enlarged. It is uncommon for children with this condition to survive beyond childhood.
2. Late infantile and juvenile GM1 (Type ll): Intermediate type ll is also called the juvenile type. Children with type ll may indeed seem to develop normally for almost the first 17 months of life, but shortly afterwards, will develop symptoms such as impaired development. They typically do not have the distinguishing cherry-red spots in their eyes, nor do they experience organ enlargement or unusual facial features. This type tends to progress slower than type l, however life expectancy is shortened due to overall developmental disability. It is important to know that it’s possible for children with late infantile onset to live until the middle years of childhood, while those with the juvenile type could potentially survive until their early 20s.
3. Chronic or adult GM1 (type lll): This type is typically the least severe of the three types of this disease. While the onset of disease varies among people, most experience symptoms in their middle teens such as dystonia (involuntary muscle tensing), with bone and spinal cord irregularities. How long a person survives can vary.

How do people get juvenile GM1 gangliosidosis?

Since this is a genetic disease, it is not possible to “catch it” by coming into contact with another patient or carrier. Instead, the genetic mutation associated with GM1 disorder is passed on from parents to their children. While both parents are carriers of this mutated gene, they typically remain largely asymptomatic.

How can juvenile GM1 gangliosidosis be treated?

Upon testing positive for juvenile GM1 gangliosidosis, it is important for parents to consult with a healthcare team of specialists, which may include physical and occupational therapists depending upon the form of the disease. Currently, there are no FDA-approved treatments. Doctors will advise on how best to treat the symptoms and discomfort for each individual child. Support may also be available.

Where can I find more information about juvenile GM1 gangliosidosis?

• NIH