Gene newly linked to inherited ALS may also play role in common dementia

February 20, 2008

Scientists at Washington University School of Medicine in St. Louis have linked a mutation in a gene known as TDP-43 to an inherited form of amyotrophic lateral sclerosis (ALS), the neurodegenerative condition often called Lou Gehrig's disease.

Researchers found the connection intriguing because studies by other groups have revealed abnormalities in the TDP-43 protein in both sporadic and inherited ALS, as well as in several other neurodegenerative disorders.

"The potential link to sporadic ALS is particularly interesting. If we can confirm TDP-43's association with inherited ALS, mutating this gene may give us a way to model sporadic ALS in laboratory animals for the first time," says senior author Nigel Cairns, Ph.D., research associate professor of neurology and pathology and immunology. "That could give us a potent tool for better understanding ALS and developing new treatments."

The study appears February 20 in Annals of Neurology. It was conducted at the Hope Center for Neurological Disorders, a partnership between the University and Hope Happens, a St. Louis-based non-profit organization dedicated to raising funds for neurological research.

Approximately 30,000 U.S. citizens have ALS, a condition that kills motor neurons, the nerve cells that control muscles. This causes gradually increasing paralysis and typically leads to death over a course of several years. Approximately five to 10 percent of all ALS cases are inherited; the rest are sporadic.

Hope Happens was founded by Christopher Hobler, a St. Louisan who developed ALS and died from the disorder in 2005. Hobler's grandfather and cousin had previously died from the disorder, and Hobler and his family founded Hope Happens to promote awareness of ALS and other neurodegenerative conditions and to raise money for research to develop new treatments and cures.

In 1993, scientists linked an inherited form of ALS to mutations in the gene for a protein called superoxide dismutase-1 (SOD1). Since then, many had thought altering the SOD1 gene's function was the most promising way to model and understand sporadic ALS.

"That has all been turned upside down in the last two years, though," says Cairns. "In that time, abnormal TDP-43 deposits have been identified in sporadic ALS cases and in some inherited forms of ALS that don't involve a SOD1 mutation."

TDP-43 is an influential regulator of messenger RNA splicing, the process that edits protein-building instructions from DNA to allow the proteins to be built properly. TDP-43 abnormalities in ALS patients have included altered folding and a chemical change known as phosphorylation, both of which can radically alter the protein's function.

As a result, several research groups have been looking for a case where a mutation in the TDP-43 gene was linked to inherited disease. The new study is the first to tentatively establish such a link. Michael Gitcho, Ph.D., a postdoctoral research associate in Dr. Cairns' lab, and colleagues found that every member of a family affected by an inherited form of ALS had a particular mutation in TDP-43. Next, they looked at 1,505 people not related to the family and unaffected by ALS. This second search found no examples of the same mutation.

Because the family they studied is small, scientists need further evidence to confirm that the mutation is causing ALS. Researchers are working to introduce the mutated human TDP-43 gene they identified in the family into a transgenic mouse model. They hope the mouse will generate a model for ALS-like pathology.

If this affirms the link, they will begin tracing the effects of the mutation on genes whose splicing is regulated by TDP-43, working to identify key links in the chain reaction that leads to motor neuron death. These links may become new targets for pharmaceutical treatments.

What they learn may also shed light on other neurodegenerative disorders. Co-author Alison M. Goate, D. Phil., the Samuel and Mae S. Ludwig Professor of Genetics in Psychiatry, notes that abnormal TDP-43 has been found in patients with frontotemporal dementia, the second most common cause of early-onset dementia after Alzheimer's disease.

"As our understanding of these diseases progresses, we're starting to see common elements," says Goate. "This protein may allow us to link together a number of important disease entities and pinpoint new targets for therapeutic intervention."

Source: Washington University in St. Louis

Explore further: What we know, don't know and suspect about what causes motor neuron disease

Related Stories

What we know, don't know and suspect about what causes motor neuron disease

June 20, 2017
Since 2014, the ice bucket challenge, which involves people pouring a bucket of icy water over their heads, has raised awareness and much-needed research funds for motor neuron disease. While research for a cure is underway, ...

Recommended for you

New approach to studying chromosomes' centers may reveal link to Down syndrome and more

November 20, 2017
Some scientists call it the "final frontier" of our DNA—even though it lies at the center of every X-shaped chromosome in nearly every one of our cells.

Genome editing enhances T-cells for cancer immunotherapy

November 20, 2017
Researchers at Cardiff University have found a way to boost the cancer-destroying ability of the immune system's T-cells, offering new hope in the fight against a wide range of cancers.

A math concept from the engineering world points to a way of making massive transcriptome studies more efficient

November 17, 2017
To most people, data compression refers to shrinking existing data—say from a song or picture's raw digital recording—by removing some data, but not so much as to render it unrecognizable (think MP3 or JPEG files). Now, ...

US scientists try first gene editing in the body

November 15, 2017
Scientists for the first time have tried editing a gene inside the body in a bold attempt to permanently change a person's DNA to try to cure a disease.

Genetic mutation in extended Amish family in Indiana protects against aging and increases longevity (Update)

November 15, 2017
The first genetic mutation that appears to protect against multiple aspects of biological aging in humans has been discovered in an extended family of Old Order Amish living in the vicinity of Berne, Indiana, report Northwestern ...

Genetic variant prompts cells to store fat, fueling obesity

November 13, 2017
Obesity is often attributed to a simple equation: People are eating too much and exercising too little. But evidence is growing that at least some of the weight gain that plagues modern humans is predetermined. New research ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.