Featured Research

from universities, journals, and other organizations

Study supports causal role in narcolepsy for common genetic variant

Date:
January 2, 2014
Source:
American Academy of Sleep Medicine
Summary:
A new study conducted across Europe found an extraordinary association between narcolepsy and a specific gene variant related to the immune system.

A new study conducted across Europe found an extraordinary association between narcolepsy and a specific gene variant related to the immune system.

Related Articles


The modified genome-wide association study involved 1,261 people with narcolepsy, representing nearly 90 percent of European patients suffering from narcolepsy with cataplexy who have complete diagnostic work-up and DNA available. They were matched with 1,422 controls. High-resolution genotyping identified genetic variants including those in the human leukocyte antigen (HLA) system, which contains genes related to immune system function. Analysis was performed by logistic regression.

Results show that participants with the HLA allele DQB1*06:02 were 251 times more likely to have narcolepsy with cataplexy than participants without the gene variant. DQB1*06:02 had a remarkably high negative predictive value of 99.32 percent, which means that nearly 100 percent of narcolepsy with cataplexy patients are DQB1*06:02 positive. Four other DQB1 alleles provided protection against narcolepsy, strongly supporting a causal role for DQB1 in narcolepsy.

"For the first time we have tested the HLA association all over Europe," said principal investigator and lead author Mehdi Tafti, professor in the Center for Integrative Genomics at the University of Lausanne and Lausanne Hospital in Switzerland. "This almost 100 percent association with HLA is somehow unique to narcolepsy and suggests a causal implication."

Recent studies suggest that narcolepsy may be caused by an autoimmune response to an environmental trigger such as an infection. In people who are genetically susceptible to narcolepsy, the immune system may respond to the trigger by mistakenly attacking and destroying brain cells that make hypocretin, a hormone that helps promote alertness.

The authors noted that DQB1*06:02 is a common gene variant that is present in about 20 percent of the general European population. As a result, DQB1*06:02 had a low positive predictive value of only 65.68 percent. However, they suggested that high-resolution genotyping could play a valuable role in diagnosing patients suspected of having narcolepsy and evaluating at-risk populations.

"For clinicians these findings indicate they should reconsider the diagnosis of narcolepsy with cataplexy in HLA DQB1*06:02 negative patients," said American Academy of Sleep Medicine spokesperson Dr. Nathaniel Watson.

According to the American Academy of Sleep Medicine, narcolepsy is a rare but often disabling sleep illness characterized by excessive sleepiness. People with narcolepsy experience repeated daily episodes of an irrepressible need to sleep or lapses into sleep, which may occur as sudden, irresistible sleep "attacks." Another common symptom of narcolepsy is cataplexy, which involves sudden muscle weakness caused by strong emotions such as laughter.


Story Source:

The above story is based on materials provided by American Academy of Sleep Medicine. Note: Materials may be edited for content and length.


Journal Reference:

  1. Tafti M; Hor H; Dauvilliers Y; Lammers GJ; Overeem S; Mayer G; Javidi S; Iranzo A; Santamaria J; Peraita-Adrados R; Vicario JL; Arnulf I; Plazzi G; Bayard S; Poli F; Pizza F; Geisler P; Wierzbicka A; Bassetti CL; Mathis J; Lecendreux M; Donjacour CE; van der Heide A; Heinzer R; Haba-Rubio J; Feketeova E; Hφgl B; Frauscher B; Benetσ A; Khatami R; Caρellas F; Pfister C; Scholz S; Billiard M; Baumann CR; Ercilla G; Verduijn W; Claas FH; Dubois V; Nowak J; Eberhard HP; Pradervand S; Hor CN; Testi M; Tiercy JM; Kutalik Z. DQB1 locus alone explains most of the risk and protection in narcolepsy with cataplexy in Europe. SLEEP, 2014;37(1):19-25.

Cite This Page:

American Academy of Sleep Medicine. "Study supports causal role in narcolepsy for common genetic variant." ScienceDaily. ScienceDaily, 2 January 2014. <www.sciencedaily.com/releases/2014/01/140102113128.htm>.
American Academy of Sleep Medicine. (2014, January 2). Study supports causal role in narcolepsy for common genetic variant. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2014/01/140102113128.htm
American Academy of Sleep Medicine. "Study supports causal role in narcolepsy for common genetic variant." ScienceDaily. www.sciencedaily.com/releases/2014/01/140102113128.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Best Tips to Curb Holiday Carbs

The Best Tips to Curb Holiday Carbs

Buzz60 (Dec. 19, 2014) — It's hard to resist those delicious but fattening carbs we all crave during the winter months, but there are some ways to stay satisfied without consuming the extra calories. Vanessa Freeman (@VanessaFreeTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Sierra Leone Bikers Spread the Message to Fight Ebola

Sierra Leone Bikers Spread the Message to Fight Ebola

AFP (Dec. 19, 2014) — More than 100 motorcyclists hit the road to spread awareness messages about Ebola. Nearly 7,000 people have now died from the virus, almost all of them in west Africa, according to the World Health Organization. Video provided by AFP
Powered by NewsLook.com
Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) — In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Buzz60 (Dec. 19, 2014) — A double-amputee makes history by becoming the first person to wear and operate two prosthetic arms using only his mind. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins