Gerstmann-Sträussler-Scheinker Disease (GSS)
(See Overview of Prion Diseases.)
Gerstmann-Sträussler-Scheinker disease is a prion disease that causes loss of coordination followed by slow deterioration of mental function. The disease is fatal, usually in about 5 years.
Like Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker disease is a prion disease that may occur anywhere in the world. However, it is much less common than Creutzfeldt-Jakob disease. It usually begins earlier in life (affecting people in their 40s rather than in their 60s) and progresses more slowly (with an average life expectancy of 5 years rather than 6 months). Gerstmann-Sträussler-Scheinker disease is a familial prion disease. That is, it runs in families.
Usually, the first symptoms are clumsiness and unsteadiness when walking. Muscle jerking (myoclonus) is much less common than in Creutzfeldt-Jakob disease. Speaking becomes difficult (called dysarthria), and dementia develops. Nystagmus (rapid movement of the eyes in one direction, followed by a slower drift back to the original position) and deafness may develop. Muscle coordination is lost. The muscles may become stiff. Usually, the muscles that control breathing and coughing are impaired, resulting in a high risk of pneumonia, which is the most common cause of death.
The diagnosis of Gerstmann-Sträussler-Scheinker disease is suggested by typical symptoms and a family history of the disease and is confirmed by genetic testing.
No effective treatment is available. Treatment of Gerstmann-Sträussler-Scheinker disease focuses on relieving symptoms.