GM-1

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Last Updated: Thursday, 08 July 2021 13:37

What is GM1 gangliosidosis?

Gangliosidosis-1 (GM-1) is a progressive neurological genetic disorder caused by the absence of a vital enzyme.  It is one of over 50 genetically inherited disorders known as Lysosomal Storage Diseases.

Dr. Landing gave the first definitive description of Gangliosidosis-1 (GM-1) in 1964, which had variously been called "Hurler variant," "pseudo-Hurler disease," and "Tay-Sachs with visceral involvement."

Dr. Caffey likely gave the earliest description of GM-1 in 1951 discussing prenatal onset of Hunter-Hurler disease.

What are the GM1 gangliosidosis symptoms?

Symptoms can appear anytime from birth to adulthood and differ depending on the age.

GM1 - Infantile Symptoms & Diagnosis

Symptoms appear within the first 6 months of age and may be apparent at birth. Early symptoms include poor appetite, weak suck and failure to thrive. Only about 50% of cases display the cherry-red spot in the back of the eye.

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GM1 - Juvenile Symptoms & Diagnosis

Symptoms appear after the first year of life, typically between ages 2 and 5, but can occur anytime during childhood. Early symptoms of GM1  include lack of coordination or clumsiness and muscle weakness such as struggling with stairs. A child may also exhibit slurred speech, swallowing difficulties and muscle cramps.

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GM1 - Late Onset Symptom & Diagnosis

Symptoms typically appear in adolescence or early adulthood, but sometimes later. Early symptoms of Late Onset GM1 include clumsiness and muscle weakness in the legs. Once diagnosed, adults often reflect back to their childhood and may notice experiencing symptoms much earlier such as not being athletic and/or speech difficulties or a stutter as a child or teenager.

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What causes GM1 gangliosidosis?

Gangliosidosis-1 GM1 disease is caused by the absence or significantly reduced level of a vital enzyme called beta-galactosidase (GLB1). Without GLB1, a fatty substance or lipid called GM-1 ganglioside accumulates abnormally in cells, especially in the nerve cells of the brain. This ongoing accumulation, also called "substrate", causes progressive damage to the cells.

The Juvenile and Late Onset forms of GM-1 occur when the mutations allow the GLB1 enzyme to function a little bit. Just a small increase in GLB1 activity is enough to delay the onset and slow the progression of symptoms.

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Who can inherit GM1 gangliosidosis?

GM 1 gangliosidosis must be inherited from parents who are carriers of the disease.  Anyone can be a carrier of GM1 gangliosidosis and not have any symptoms. When both parents are carriers, each child has a 25% of having the disease. The carrier rate for the general population is 1/250. Some evidence suggests people of Irish / British Isle descent have an increased risk over the general population between 1/50 to 1/150. French Canadians, Louisiana Cajuns and Ashkenazi Jews are all considered high risk with a carrier rate of 1/27.

Talk to your doctor about Genetic Counseling to discuss your options before starting your family.

What research is being done on GM1 gangliosidosis?

To date, there is no treatment or cure for GM-1 disease but there is exciting, ongoing research and NTSAD is committed to funding and supporting the efforts to finding a cure while helping families to cope with GM1.

GM1 shares biochemical traits with other diseases including Tay-Sachs and Sandhof, thus research on any of these diseases may benefit the others. Treating these diseases falls into two general categories: restoring the missing enzyme or decreasing the waste accumulation. The scientific community generally agrees that no single therapy will cure these diseases but that rather a combination of approaches will slow, halt and even reverse the damage caused by these diseases.

Research has included Gene Therapy, Molecular Chaperone, Substrate Inhibition, Stem Cells, and Bone Marrow Treatment.

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Support: Coping with GM1

NTSAD is the largest organization dedicated to supporting families with members having GM1, Sandhoff, Tay-Sachs or Canavan disease. We have compiled many resources for family members, provide weekly and monthly updates on events and research, and organize an annual family conference specifically for family members.

Family support web pages are grouped based on the age of the family member having the disease.

Infantile & Juvenile Support

Late Onset Support

GM1 Family Information Packet

Someone you love has been diagnosed with a disease without a treatment or cure. You don't know what to do. NTSAD offers a free information packet that includes materials on;

• symptom management
• research updates
• how to cope

Request it today by completing our online request form: Contact Us.

More GM1 Online Resources

U.S. National LIbrary of Medicine
Genetics Home Reference: GM1 Gangliosidosis
National Center for Biotechnology Information
Gangliosidosis generalized GM1 type 1 - infantile
Gangliosidosis generalized GM1 type 2 - juvenile
Gangliosidosis GM1 type 3 - adult
Medical Publications on GM1

U.S. National Institute of Health
GM1 Gangliosidosis Clinical Trials
Genetic & Rare Disease Info Center, GM1 type 1 - infantile
Genetic & Rare Disease Info Center, GM1 type 2 - juvenile
Genetic & Rare Disease Info Center, GM1 type 1 - adult

Genetic Alliance disease research
Gangliosidosis GM1
Gangliosidosis generalized GM1 type 1 - infantile
Gangliosidosis generalized GM1 type 2 - juvenile
Gangliosidosis GM1 type 3 - adult

Orphanet, Online Rare Disease & Orphan Drugs
GM1 Summary and Online Resources

OMIM database of of human genes and genetic phenotypes
Gangliosidosis generalized GM1 type 1 - infantile
Gangliosidosis generalized GM1 type 2 - juvenile
Gangliosidosis GM1 type 3 - adult

GM1 Gangliosidosis-1 Infantile Symptoms

Details

Last Updated: Wednesday, 29 April 2015 13:14

What are the symptoms of infantile GM1?

First signs - A baby with Classic Infantile GM1 gangliosidosis displays symptoms within the first 6 months.   Symptoms may be apparent at birth. Early symptoms include poor appetite, weak suck and failure to thrive. Only about 50% of cases display the cherry-red spot in the back of the eye.

Gradual Loss of skills - Infantile GM1 gangliosidosis children never learn to sit up or crawl, have generalized poor muscle strength, demonstrate progressive inability to swallow and have difficulty breathing.  Some children also have an enlarged heart, cardiomegaly.

By Age 2 and beyond - Most children experience recurrent seizures by age 1 and eventually lose muscle function, and mental function and sight, becoming mostly non-responsive to their environment.

How does an infant get diagnosed with GM1?

Babies affected by the infantile form of GM1 gangliosidosis are frequently diagnosed by the cherry-red spot on the retina of the eye.  Initially many parents notice developmental delays but pediatricians often dismiss these concerns by stating "every baby develops differently" and "the baby will catch up". Often at about 10-14 months of age, children may start to exhibit trouble tracking and/or focusing with their eyes, so parents schedule an appointment for an eye exam.   The cherry-red spot is quickly seen and an initial diagnosis of Tay-Sachs or similar devastating disease is made.

Diagnosis can also be made by a neurologist or geneticists and the completion of a metabolic evaluation.

How do I care for an infant having GM1?

There is no treatment or cure for GM1 gangliosidosis disease but there are ways to manage symptoms. These range from life-extending interventions like a feeding tube to comfort measures like massage to promote relaxation.

Respiratory health and seizure management are the two main symptom management challenges in Infantile GM1 gangliosidosis.

Recommendations for managing the symptoms appear in Infantile & Juvenile Support.

Newly diagnosed families should read Philosophy of Care, a framework of care goals and values to help you make the best choices for your child and family.

GM1 Family Information Packet

NTSAD offers a free information packet that includes materials on the following topics.

• symptom management
• research updates
• how to cope

Request it today by completing our online request form: Contact Us.

GM1 Gangliosidosis-1 - Juvenile Symptoms

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Last Updated: Wednesday, 29 April 2015 13:12

What are the symptoms of Juvenile GM1?

First signs - Early symptoms of GM1 gangliosidosis include lack of coordination or clumsiness and muscle weakness such as struggling with stairs. A child may also exhibit slurred speech, swallowing difficulties and muscle cramps.

Gradual Loss of skills - Over time children with GM1 gangliosidosis slowly decline, losing their ability to walk, eat on their own and communicate. Children are prone to respiratory infections and often experience recurrent bouts of pneumonia.  Many have seizures.

Range of Severity - Juvenile GM1 gangliosidosis has a broad range of severity. In most cases, the earlier the first signs are observed, the more quickly the disease will progress. For example, a child with first symptoms at age 2 will decline faster than a child with first symptoms at age 5.

How does Juvenile GM1 get diagnosed?

GM1 gangliosidosis is diagnosed through a blood test to check the level of beta-galactosidase (GLB1). A follow-up DNA test may be recommended.  Any doctor can order the GM-1 GLB1 blood test. Often, diagnosis is made by a neurologist or geneticist.

Children affected by Juvenile form of GM1 gangliosidosis disease do not exhibit the tell-tale cherry-red spot in the eye.  This can make the road to diagnosis long and challenging. Unfortunately many healthcare providers are not aware of the rare juvenile forms of these diseases and dismiss the initial diagnosis due to the age of the child. 

How do I care for a child with Juvenile GM1?

There is no treatment or cure for GM1 gangliosidosis disease but there are ways to manage symptoms. These range from life-extending interventions like a feeding tube to comfort measures like massage to promote relaxation.

Progressive loss of ambulatory skills followed by respiratory health and seizure management are the main symptom management issues in Juvenile GM1 gangliosidosis. 

Recommendations for managing the symptoms appear in Infantile & Juvenile Support

Newly diagnosed families should read Philosophy of Care, a guide to help parents develop a care plan and care goals to aid in major care choices.

GM1 Family Information Packet

Someone you love has been diagnosed with a disease without a treatment or cure. You don't know what to do. NTSAD offers a free information packet that includes materials on;

• symptom management
• research updates
• how to cope

Request it today by completing our online request form: Contact Us.

GM1 Gangliosidosis-1 - Late Onset Symptoms

Details

Last Updated: Wednesday, 29 April 2015 13:11

What are the symptoms of adult Late Onset GM1?

First signs - Early symptoms of Late Onset GM1 gangliosidosis include clumsiness and muscle weakness in the legs. Once diagnosed, adults often reflect back to their childhood and may notice experiencing symptoms much earlier such as not being athletic and/or speech difficulties or a stutter as a child or teenager.

Gradual Loss of skills - Over time, adults with Late Onset GM1 gangliosidosis slowly decline. Adults frequently require more mobility assistance, i.e. cane to walker to wheelchair. Many experience speech and swallowing difficulties but few require a feeding tube.

How is Late Onset GM1 Diagnosed?

Late Onset GM1 gangliosidosis may be hard to diagnosis. Some adults go 5 or more years before learning their true diagnosis. It may sometimes be misdiagnosed as Multiple Sclerosis or ALS.

GM1 gangliosidosis is diagnosed through a blood test to check the level of beta-galactosidase (GLB1). A follow-up DNA test may be recommended.  Any doctor can order the GM1 gangliosidosis GLB1 blood test. Often, diagnosis is made by a neurologist or geneticist.

Adults affected by the adult form of GM1 gangliosidosis disease do not exhibit the tell-tale cherry-red spot.  This can make the road to diagnosis long and challenging. Unfortunately many healthcare providers are not aware of the rare adult forms of these diseases and dismiss the initial diagnosis due to the age of the patient.

Adults that display mental health symptoms before physical symptoms often experience the longest road to diagnosis.

Many affected adults express mixed emotions when finally receiving their diagnosis. After years of not knowing the cause of their progressive symptoms, they may experience a certain amount of relief when an accurate diagnosis is determined. At the same time, GM1 gangliosidosis is a difficult diagnosis to receive and there can be a sense of regret and frustration.

Living with adult Late Onset GM1

Late Onset GM1 gangliosidosis is a challenging and debilitating disorder but doesn't always shorten life span like the childhood forms of Sandhoff. Visit Tay-Sachs, Sandhoff and GM-1 Late Onset Support to learn more about living a full and empowered life with Late Onset GM1 gangliosidosis.

GM1 Family Information Packet

NTSAD offers a free information packet that includes materials on the following topics.

• symptom management
• research updates
• how to cope

Request it today by completing our online request form: Contact Us.