17% of sporadic cases of Charcot’s disease are in fact due to rare genetic variations.
- 90% of patients with ALS have no family history.
- According to this study, 17% of non-family cases are caused by a genetic mutation.
- Patients with ALS are four times more likely to have a variation associated with the disease.
- Charcot’s disease is an incurable degenerative disease. It usually causes the patient to die within 3 to 5 years of diagnosis.
- 800 new cases are diagnosed each year. They usually occur between the ages of 50 and 70.
Genes play a heavier role than estimated in amyotrophic lateral sclerosis (ALS). The vast majority of cases are said to be sporadic. But even without a family history, genetic abnormalities are more often seen in patients. A study conducted in the United States shows this in Neurology.
87 patients with the sporadic form of Charcot’s disease underwent genetic screening for the sake of this study. An important choice: only 10% of cases are of family origin. And the causes of the sporadic forms are poorly understood. According to this work, genes play a significant role.
17% genetic causes
Genetic analyzes reveal 33 variations strongly associated with this degenerative disease. Comparing them to 300 healthy people, the researchers found that these variants were more often present in sick people.
A quarter of volunteers diagnosed with ALS carry rare changes compared to 15% in the healthy group. But these changes do not increase the risk of developing the disease, even if they are associated with it.
On the other hand, if only potentially dangerous variants are observed, the patients are clearly distinguished. They are four times more likely to carry a risk mutation compared to healthy participants. 17% of ALS cases are therefore caused by a genetic mutation.
“More work is needed to discover other genetic factors that trigger the disease, and to define non-genetic factors involved in ALS,” said Summer Gibson, lead author of this study.
New therapeutic avenues
But knowing the genetic part at work in Charcot’s disease is important. Because by observing only the symptoms, it is impossible to distinguish a sporadic form from a family form. And as Summer Gibson reminds us, the hereditary aspect of the pathology can go unnoticed. “In some families, people may die from other causes before ALS develops, or suffer from a misdiagnosis,” explains the researcher.
Identifying the genes at work can also help teams develop new therapeutic approaches. At present, hardly any treatment makes it possible to slow down or stop the progression of the disease. In the United States, only two molecules are available on the market.
The last allows to preserve the motor function a little longer. This is the key point in the fight against the disease. The destruction of motor neurons results in an inability to use the muscles of the body, which leads to complete paralysis of the muscles. Often, the inability to swallow or breathe results in death of patients.
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