Molecular Genetics of Essential Tremor

Abstract

Essential tremor (ET) is a movement disorder characterised by involuntary and rhythmic shaking, especially in the hands. The primary symptom associated with ET is an action tremor, which occurs with the purposeful use of a body part, like the hand. ET has a strong genetic component as 50–70% of cases have a familial history where transmission is typically autosomal dominant. The high rate of misdiagnosis, which is in part due to the absence of biomarkers, imaging or genetic markers, complicates the identification of genetic risk factors. Another challenging aspect is the overlapping clinical and pathological features between ET and Parkinson's disease (PD), along with the evidence of increased odds of developing PD when affected by ET. Decades of research have identified several ET loci and candidate genes, albeit replication studies, when available, yielded mixed results, and in most cases, evidence supporting variant causality remains poor. Nonetheless, these associations provide valuable insights into the complexity of the genetics underlying the disorder.

Key Concepts

  • Essential tremor is a neurological disorder characterised by involuntary and rhythmic shaking.
  • The causes of essential tremor are unknown.
  • Strong evidence supports high heritability for essential tremor.
  • Decades of research have suggested multiple loci and genes associated with the disorder.
  • Few of these genetic associations have been replicated in independent cohorts.

Keywords: essential tremor; genetics; movement disorder; heritability; Parkinsonism; linkage study; genome‐wide association study; high‐throughput sequencing

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Houle, Gabrielle, Dion, Patrick A, and Rouleau, Guy A(Jun 2018) Molecular Genetics of Essential Tremor. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0028103]