Perhaps you have heard the expression “genetic vulnerability.” For example, it is often said that individuals with a family history of alcoholism have a genetic vulnerability for this addition. This is supported by scientific studies. The National Council on Alcoholism and Drug Addiction reports, “Research shows that genes are responsible for about half the risk for alcoholism and addiction, and while genetics are not the sole determinant, their presence or absence may increase the likelihood that a person will become alcohol or drug dependent.”1
This does not mean that genes are the voice of doom. Rather, they indicate a predisposition or tendency for a condition or illness to become active, even though the exact conditions that trigger this may be unknown.
Genes and essential tremor
Essential tremor (ET) is the most common movement disorder. Often misdiagnosed as Parkinson’s disease, it is characterized by uncontrollable shaking (tremors) of the hands, head, voice or other body part. It is estimated that about half of ET cases include a family history. This means that at least one relative – but often relatives across two or more generations – were known to have ET.
In familial ET, the prevailing genetic theory has been that the predisposition occurs as a result of inheriting an autosomal dominant trait, meaning that a single copy of an abnormal gene from just one parent carries the vulnerability (other modes of inheritance are also being researched).2
The great mystery, of course, is which gene or genes? According to the Mayo Clinic, “a specific gene hasn’t been identified.”3
New discovery points to 3 genes
In December, 2016 the journal Brain published a study titled “Genome-wide association study in essential tremor identifies three new loci.”4 The study involved a large team of researchers from multinational centers. It included 2807 ET patients with 6441 matched non-ET controls in a two-stage genome-wide association study.
The team discovered a strong link between a gene called STK32B and essential tremor. They also discovered two other genes with some link to ET, though not a strong one. The specific action of any of these three genes in activating tremors is as yet unclear. However, the association of STK32B with ET is important enough for all of the institutions involved to put out a call to ET patients everywhere in hopes of recruiting 10,000 more participants willing to have their genomic profile analyzed. This large number is needed because, as one news item explains, “identifying disease causes at the cellular level involves great financial burden, time and most importantly a large group of participants willing to be put under the microscope.”5
MRgFUS at the Sperling Medical Group
The Sperling Medical Group encourages ET patients to enroll in the study. At the time the study was published, Parkinson’s News Today posted that anyone interested in taking part in the study should contact Vessela Zaharieva, the research coordinator, by email at firstname.lastname@example.org.
It will undoubtedly take many long years to unravel the genomics that underlie ET. However, for patients with severe, life-impairing hand tremors, our Group offers a new, FDA-approved treatment called MR-guided Focused Ultrasound (MRgFUS) using Neuravive technology. MRI guidance allows a brain intervention that needs no incisions or holes drilled into the skull. The treatment uses hundreds of “beams” of ultrasound aimed at a small part of the thalamus, the VIM nucleus. This nucleus acts as a relay station, forwarding abnormal brain signals to the hands, causing the tremors. The focused ultrasound treatment basically blocks it from sending the signals. The result is immediate and lasting.
Learn more about Neuravive at the Sperling Medical Group.
4Müller SH, Girard SL, Hopfner F1, Merner ND, Bourassa CV et al. Genome-wide association study in essential tremor identifies three new loci. Brain. 2016 Dec;139(Pt 12):3163-3169. Epub 2016 Oct 20.