Gerstmann-Straussler-Scheinker disease (GSS) is a type of prion disease. Prion diseases are a group of conditions that affect the nervous system. The main feature of GSS is a progressive degeneration of the cerebellum (a part of the brain that controls coordination, balance, equilibrium and muscle tone), as well as different degrees of dementia. Signs and symptoms generally develop between ages 35 and 50 years and may include weakness in the legs, poor reflexes, abnormal sensations, progressive ataxia, cognitive dysfunction, slurred speech, and spasticity. On average, people affected by GSS survive approximately 60 months (range 2 to 10 years) following diagnosis. It is caused by changes (mutations) in the PRNP gene and inheritance is autosomal dominant. Treatment is based on the signs and symptoms present in each person. For information on other prion diseases, please visit GARD's Creutzfeldt-Jakob disease and fatal familial insomnia pages.

Gerstmann-Straussler-Scheinker disease (GSS) is caused by certain changes (mutations) in the PRNP gene. PRNP encodes a protein called prion protein. Although the exact function of this protein is unknown, it appears to play an important role in the human brain and other tissues throughout the body. People affected by GSS generally have mutations in the PRNP gene that result in the production of an abnormally shaped prion protein. The abnormal protein builds up in the brain, forming clumps that damage or destroy neurons (nerve cells). This loss of brain cells leads to the signs and symptoms of GSS.

Signs and symptoms of Gerstmann-Straussler-Scheinker disease generally develop between the ages of 35 and 50 years. Affected people may experience:

• Progressive ataxia, including clumsiness, unsteadiness, and difficulty walking
• Cognitive dysfunction leading to bradyphrenia (slowness of thought processing) and dementia of different degrees
• Dysarthria (slurred speech)
• Nystagmus (abnormal eye movements)
• Spasticity (rigid muscle tone)
• Visual disturbances, sometimes leading to blindness
• Lack of coordination in swallowing
• Deafness
• Parkinsonian features (present in some families).

The treatment of Gerstmann-Straussler-Scheinker disease (GSS) is based on the signs and symptoms present in each person. There is currently no cure for the condition and no known treatments to slow its progression. GeneReviews' Web site offers more specific information about the treatment and management of GSS and other genetic prion diseases. The National Prion Disease Surveillance Center is charged with collecting and recording all cases of prion disease in the US. They should be notified regarding all cases of suspected prion disease.

People with Gerstmann-Straussler-Scheinker disease (GSS) survive for an average of 5 years after diagnosis. The range is 2 to 10 years. In the late stages, people develop mobility problems usually due to severe ataxia. They may also have slurred speech and trouble swallowing.

Gerstmann-Straussler-Scheinker disease (GSS) is inherited in an autosomal dominant manner. Every cell of the body has two copies of a gene. In autosomal dominant disorders, to be affected, a person needs a change (mutation) in only one copy of the responsible gene in each cell. In some cases, an affected person inherits the mutation from an affected parent. Other cases may result from new (de novo) mutations in the gene. These cases occur in people with no family history of the disorder. A person with GSS has a 50% chance with each pregnancy of passing along the mutated gene to his or her child.