In the past, research has suggested that there was a genetic component to essential tremor (ET), a nervous system disorder. According to Medscape, researchers recently expanded on this understanding by exploring which type of genetic loci were associated with an increased risk of essential tremor. After a genome-wide association study and meta-analysis, researchers identified five novel risk loci.
If you are interested in reading the full study results, you can find them published in JAMA Neurology.
About the Research
How can researchers, scientists, and doctors best understand the underlying biological mechanisms behind essential tremor? This study sought to both enrich knowledge as to how essential tremor develops, while also potentially uncovering therapeutic targets. While prior research has implicated cerebellar issues as associated with essential tremor, the research around the actual genetics of the condition is complex and inconsistent.
Within this study, researchers collected data from 7,177 people with essential tremor and 475,877 controls over a 9.5 year period. A majority of people in both cohorts were female. Next, researchers evaluated 6,892,661 genetic markers. Findings include:
- There were five genetic loci associated with an increased risk of essential tremor. Altogether, the heritability associated with these loci was 18%. To learn more about genetic loci, check out this helpful guide from the National Human Genome Research Institute.
- Loci associated with increased essential tremor risk were most significant in the cerebellum and neuronal axons.
- Overall, there was a 30% genetic overlap with Parkinson’s disease. This suggests that the genetic loci which increase essential tremor risk may also increase the risk of developing Parkinson’s disease. There was also a genetic relationship with depression.
Essential Tremor (ET)
Essential tremor (ET) is a progressive neurological disorder which impacts an estimated 1% of people globally. The disorder is characterized by involuntary and rhythmic shaking (tremors) which often begin on one side of the body before progressing. Tremors may occur in different areas of the body, but most often affect the hands or arms. While these tremors are not necessarily dangerous to those affected, it may reduce quality-of-life (QOL). Typically, essential tremor affects those aged 40 or older, though it can also occur in childhood or young adulthood. Changes in temperature, smoking cigarettes, being hungry, feeling anxious or stressed, or being fatigued may also worsen tremors. Symptoms and characteristics include:
- Involuntary shaking or trembling, including shaking or nodding of the head
- Difficulty eating, talking, writing, shaving, putting on makeup, or performing other similar movements
- Abnormal gait
- Shaking or quivering voices