For 50 to 70% of patients with essential tremors, there is a family history of the disease. It is a hereditary pathology with dominant autosomal transmission.
Causes of essential tremor
Several genes were identified in different patient groups and by different teams, but the results were not replicated according to the population groups studied. Although the disorders of persons with essential tremor are very similar, the current hypothesis is that the origin of essential tremor does not have a single cause with heterogeneity in causes and evolution from person to person. There are also sporadic (isolated) cases of the disease, i.e. patients with no family history. Genetic research has shown that there is a genetic predisposition to disease, that is, certain DNA variants increase the risk of developing the disease but are not inherited.
The risk of a person with a dominant autosomal mutation transmitting the mutation and thus the disease to his or her child is therefore 50%.
There are also sporadic cases of the disease, i.e. patients with no family history. Genetic research has shown that there is a genetic predisposition to disease, that is, certain DNA variants increase the risk of developing the disease but are not inherited.
The biological mechanisms responsible for essential tremor are partially understood. Current research tells us that brain circuits related to the cerebellum, the brain region involved in controlling movement and its accuracy, play a role in the disease. The cerebellum also has the function of coordinating movements and stabilizing the balance, so over time patients may have more difficulty coordinating the actions of the upper limbs, and may have balance disorders while walking.
The modulation of cerebellum circuits is the basis for treatments such as deep brain stimulation of the thalamus (a structure at the heart of the cerebral circuit of the cerebellum), or highly focused lesion of a small area of the thalamus by gamma rays (Gamma-knife) or focused ultrasound (FUS)