What is Gerstmann-Straussler-Scheinker Disease?
Gerstmann Straussler Scheinker disease, also known as GSS, is a rare, fatal condition and is classed as a prion disease or a transmissible spongiform encephalopathy. Prion diseases are progressive neurological diseases that cause coordination, balance and cognitive function to deteriorate with time. Another example of a prion disease is Creutzfelt-Jakob disease (CJD). Prion diseases can affect humans and animals.
GSS was first diagnosed in an Austrian family who demonstrated symptoms of gradual neurological degeneration, including a lack of stability on the feet, loss of coordination, weakness in the muscles and cognitive decline. This is a very severe condition that usually causes death within 5 years. It tends to affect people earlier in life than CJD and the symptoms progress at a slower pace.
GSS is named after the people who first shed light on the condition: Josef Gerstmann, Ernst Straussler and Ilya Scheinker.
What causes Gerstmann Straussler Scheinker disease?
GSS is a prion disease, which means that it caused by prions, a small group of proteins that employs resistance against proteases. In the case of GSS, studies have found that an alteration on chromosome 20 in the vast majority of affected individuals. GSS occurs when proline changes to leucine on this specific chromosome. Researchers have found that this change is noticeable in the PRP (prion protein gene) of most people who present with the disease, which suggest that this change is necessary to develop GSS.
Who gets Gerstmann Straussler Scheinker disease?
In most cases, GSS is familial, which means that it runs in families and you have a much higher risk of developing GSS if you have a close family member with the syndrome. It is a very rare condition and it is not known exactly how many people are affected. However, it is estimated to be between 1 and 10 people per every 100,000,000. Symptoms tend to develop after the age of 30 years old.
Symptoms of Gerstmann Straussler Scheinker disease
The first symptoms of GSS tend to be a lack of steadiness on your feet and general clumsiness and as the disease progresses. Additional symptoms occur, including impaired speech, dementia, lack of coordination, loss of memory and nystagmus. Nystagmus is a term used to describe the rapid movement of the eyes in one direction, which is then followed by slower movement to return the eyes back to the centre. Sometimes, the muscles become tense and this restricts movement and the muscles located in the chest may stiffen, resulting in breathing difficulties and problems with coughing.
Typically, symptoms tend to progress over a 5 year period and the most common cause of death is pneumonia.
Diagnosing Gerstmann Straussler Scheinker disease
GSS is usually diagnosed based on the presentation of symptoms and genetic testing, which can confirm the codon abnormality on chromosome 20.
If GSS is confirmed, close members of the individual’s family will have a higher risk of developing GSS. If the chromosomal abnormality is detected, but symptoms have not yet developed, it is almost certain that they will become apparent in the future.
Is there a cure for Gerstmann Straussler Scheinker disease?
There is currently no cure for GSS and there is no treatment able to slow the progression of symptoms. However, there are therapies that may help to ease symptoms and enhance quality of life.
What is the prognosis for patients with Gerstmann Straussler Scheinker disease?
Unfortunately, there is no cure for GSS and the disease is fatal. Typically, people tend to survive for around 5 years after diagnosis, but this can vary from a few months to 13 years.