- Beta galactosidase 1 deficiency
- GLB 1 deficiency
- Classic infantile (type 1) GM1 gangliosidosis is the most severe type, with onset shortly after birth (usually within 6 months of age). Affected infants typically appear normal until onset, but developmental regression (loss of acquired milestones) eventually occurs. Signs and symptoms may include neurodegeneration, seizures, liver and spleen enlargement, coarsening of facial features, skeletal irregularities, joint stiffness, a distended abdomen, muscle weakness, an exaggerated startle response to sound, and problems with gait (manner of walking). About half of people with this type develop cherry-red spots in the eye. Children may become deaf and blind by one year of age. Affected children typically do not live past 2 years of age.
- Juvenile (type 2) GM1 gangliosidosis is considered an intermediate form of the condition and may begin between the ages of 1 and 5. Features include ataxia, seizures, dementia, and difficulties with speech. This type progresses more slowly than type 1, but still causes decreased life expectancy (around mid-childhood or early adulthood).
- Adult (type 3) GM1 gangliosidosis may cause signs and symptoms to develop anywhere between the ages of 3 and 30. Affected people may have muscle atrophy, corneal clouding and dystonia. Non-cancerous skin blemishes may develop on the lower part of the trunk of the body. Adult GM1 is usually less severe and progresses more slowly than other forms of the condition.
The Human Phenotype Ontology provides the following list of signs and symptoms for GM1 gangliosidosis. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms.
The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature.
The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined.
Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
- GM1 gangliosidosis. Genetics Home Reference. July 2010; http://ghr.nlm.nih.gov/condition/gm1-gangliosidosis. Accessed 4/3/2012.
- NINDS Gangliosidoses Information Page. National Institute of Neurological Disorders and Stroke (NINDS). October 2011; http://www.ninds.nih.gov/disorders/gangliosidoses/Gangliosidoses.htm. Accessed 4/3/2012.
- Tegay D. GM1 Gangliosidosis. eMedicine. March 29, 2012; http://emedicine.medscape.com/article/951637-overview. Accessed 4/3/2012.
- About Gangliosidosis-1 (GM-1). National Tay-Sachs and Allied Diseases Association, Inc.. http://www.ntsad.org/index.php/the-diseases/gm-1. Accessed 4/3/2012.