Snapshot: What is a Genome-Wide Association Study (GWAS)?

A genome is a person’s complete set of DNA which provides the instructions to make and maintain their body’s functions. Throughout the entire genome, there are genetic differences between individuals known as single nucleotide polymorphisms or SNPs (pronounced “snips”). These variations may be unique or may occur in many people. Normally, these SNPs do not directly cause diseases. But SNPs can sometimes be associated with diseases, and can provide interesting and potentially important information. A genome-wide association study (GWAS) looks at the genomes of many individuals to identify these variations, with the goal of linking more of these variations to particular diseases.

a mural of A, C, T, G repeated over and over again fading off into the distance. It is the genetic code of DNA.
An art piece of repeating A, T, C, and G DNA base pairs, which encode our entire genome. Photo by Stefano on Flickr.

What can these types of studies tell us?

Scientists have gathered plenty of information from GWAS. Once these genetic variations are identified, researchers can use this information to learn more about how diseases occur and affect certain people. For example, GWAS have successfully identified genetic variations that can contribute to diabetes, obesity, and heart disease.

These kinds of studies can also help with creating personalized medicine – where different strategies can be used by doctors to treat patients based on their genetic makeup. This can allow doctors to give patients the most effective treatments, while limiting bad side effects.

How are these kinds of studies conducted?

Researchers typically look at two groups of people: individuals with the disease that is being studied, and people without the disease. DNA is obtained from people in each group to be studied, typically through a blood sample, or skin cells. In order for these studies to work, researchers try to look at as many people as possible. It is a big task, and requires not just hundreds, but thousands of participants! This allows researchers to be confident in the conclusions that they make.

In the early 2000’s, researchers mapped out the complete human genome. Since then, more genetic information from more people have been catalogued. Databases have been created that make it easier for researchers to compare new genomes to ones that have already been sequenced. This makes it quicker and easier to identify genetic variations and how they can contribute to disease.

What has GWAS taught us about SCA?

Some forms of Spinocerebellar ataxia (SCAs) are members of a larger group of diseases known as polyglutamine diseases. This group of diseases are caused by an abnormally long stretch of repetitive segments in the DNA. Scientists have identified that more repeats generally correspond with earlier disease onset, however, this is not always the case. Therefore, scientists have established that disease onset may be affected by other things, such as their environment or other parts of their genome or genetic factors. If researchers can identify these genetic factors, it could improve how these diseases are treated.

The cells in your body are equipped with machinery that helps identify and repair damage to DNA that occurs thousands of times a day from normal cellular processes or the environment (such as sun damage). A few years ago, GWAS revealed that genes involved in these pathways could affect SCA disease onset, and this opened up a new and exciting route of discovery for scientists! Many scientists are currently exploring this route, and more will be done in the coming years to see if we can find new therapies.

If you are interested in reading more about this GWAS report, check out our summary on the paper.

If you would like to learn more about Genome-Wide Association Studies, take a look at these resources by the National Human Genome Research Institute and MedlinePlus.

Snapshot written by Dr. Claudia Hung, edited by Dr. Ray Truant and Celeste Suart.

Spotlight: The Neuro-D lab Leiden

Principal Investigator: Dr. Willeke van Roon-Mom

Location: Leiden University Medical Centre, Leiden, The Netherlands

Year Founded: 1995

What disease areas do you research?

What models and techniques do you use?

A group photo of members of the Neuro-D lab Leiden standing outside on a patio.
This is a group picture taken during our brainstorm day last June. From left to right: Boyd Kenkhuis, Elena Daoutsali, Tom Metz, Ronald Buijsen, Willeke van Roon-Mom (PI), David Parfitt, Hannah Bakels, Barry Pepers, Linda van der Graaf and Elsa Kuijper. Image courtesy of Ronald Buijsen.

Research Focus

What is your research about?

The Neuro-D research group studies how diseases develop and progress at the molecular level in several neurodegenerative diseases. They focus on diseases that have protein aggregation, where the disease proteins clump up into bundles in the brain and don’t work correctly.

We focus strongly on translational research, meaning we try to bridge the gap between research happening in the laboratory to what is happening in medical clinics. To do this we use more “traditional” research models like animal and cell models. But we also use donated patient tissues and induced pluripotent stem cell (iPSC) models, which is closer to what is seen in medical clinics.

Our aim is to unravel what is going wrong in these diseases, then discover and test potential novel drug targets and therapies.

One thing we are doing to work towards this goal is identifying biomarkers to measure how diseases progress over time. To do this, we use sequencing technology and other techniques to look at new and past data from patients.

Why do you do this research?

So far there are no therapies to stop the progression of ataxia. If we can understand what is happening in diseases in individual cells, we can develop therapies that can halt or maybe even reverse disease progression.

Identifying biomarkers is also important, because it will help us figure out the best time to treat patients when we eventually have a therapy to test.

Stylized logo for the Dutch Center for RNA Therapeutics
The Neuro-D lab Leiden is part of the Dutch Center for RNA Therapeutics, which focuses on RNA therapies like antisense oligonucleotides. Logo designed by Justus Kuijer (VormMorgen), as 29 year old patient with Duchenne muscular dystrophy.

Are you recruiting human participants for research?

Yes, we are! We are looking for participants for a SCA1 natural history study and biomarker study. More information can be found here. Please note that information about this study is only available in Dutch.

Fun Fact

All our fridges and freezers have funny names like walrus, seal, snow grouse and snowflake.

For More Information, check out the Neuro-D lab Leiden website!


Written by Dr. Ronald Buijsen, Edited by Celeste Suart

Spotlight: The Truant Lab

Truant lab logo of a brain. "Bright minds fixing sick brains"

Principal Investigator: Dr. Ray Truant

Location: McMaster University, Hamilton, Ontario, Canada

Year Founded: 1999

What disease areas do you research?

  • SCA1
  • SCA7
  • Huntington’s Disease
  • Parkinson’s Disease

What models and techniques do you use?

  • Human cell biology
  • High content screening
  • Biophotonics
  • Microscopy

Research Focus

What is your research about?

We are looking into the role of oxidative DNA damage as a trigger to diseases like ataxia and neurodegeneration. We examine the roles of the disease proteins (ataxin-1, ataxin-7, etc,) and genes which modify or change disease that are involved with DNA damage repair.

Why do you do this research?

We are looking at what triggers the very first steps of disease. If we can understand this, we can design a treatment to stop it from happening in the first place.

Research team of 10 holding a sign which reads "We are Ataxia Aware"
Group picture of the Truant Laboratory celebrating International Ataxia Awareness Day 2019.

Fun Lab Fact

All our fridges in the laboratory are named after Game of Thrones characters! (We have several proud nerds in the lab)

For More Information, check out the Truant Lab Website!

We have an open lab notebook blog where our post-doctoral fellow Dr. Tam Maiuri post updates on her experiments in real-time! We plan to launch an ataxia open notebook in Winter 2021.


Written by Ray Truant, Edited by Celeste Suart

Spotlight: The Watt Lab

Watt lab logo of a neuron

Principal Investigator: Dr. Alanna Watt

Location: McGill University, Montreal, Canada

Year Founded: 2011

What disease areas do you research?

What models and techniques do you use?

Research Focus

What is your research about?

We are interested in how the cerebellum influences motor coordination in both the healthy brain and in models of disease and aging. By identifying changes in the cerebellum underlying ataxias and aging, we hope to discover new treatments for patients.

Why do you do this research?

We want to understand how the cerebellum works and use this knowledge to understand the changes in the cerebellum that lead to ataxia. As a lab, we are particularly interested in studying rare disorders like SCA6 and ARSACS.

These disorders have limited treatment options. We hope that by understanding how the cerebellum works differently in these disorders, we will be able to identify new treatments to help ataxia patients.

We are also interested in identifying common changes between different types of ataxia, to find out whether treatments identified in one form of ataxia might also help other ataxia patients.

Six slippers with a variety of designs, includes brain cells and mice

Fun Lab Fact

We got together and made our own slippers to keep cozy in our office. If you look at the picture closely you might be able to spot some cells from the cerebellum on some of them!

Image courtesy of Anna Cook.

For More Information, check out the Watt Lab Website!


Written by The Watt Lab, Edited by Celeste Suart

You asked, We listened: Introducing SCAsource Spotlights

Hi everyone! This is a quick message from the volunteers behind SCAsource. About a year ago we conducted a feedback study to ask what we were doing well and what we could change or improve. Some of the changes we hoped to introduce back in the spring were delayed due to COVID-19.

But we are so excited to introduce to you one of the changes we are making! We are adding a new article type: SCAsource Spotlights.

photo studio with white wooden framed wall mirror
Photo by Alexander Dummer on Pexels.com

One of the things you told us you wanted to know more about was who is doing ataxia research. What labs exist? Where are they located? What questions are they asking? Who are these researchers?

SCAsource Spotlights will be able to shed some light on this. They will be short profiles of ataxia laboratories around the world. In addition to what science is going on in these labs, each Spotlight will also include a fun fact about something that makes that research group unique.

Please let us know how you like this new article type! Our first Spotlight will be on the Watt Lab from McGill University in Montreal, Canada!

If you are from an ataxia lab and want us to do a Spotlight on you, please get in touch with us through our contact page.