Featured Research

from universities, journals, and other organizations

Lack Of Fragile X And Related Gene Fractures Sleep

Date:
June 27, 2008
Source:
Baylor College of Medicine
Summary:
Lack of both the fragile X syndrome gene and one that is related could account for sleep problems associated with the disorder, which is the common cause of inherited mental impairment.

Lack of both the fragile X syndrome gene and one that is related could account for sleep problems associated with the disorder, which is the common cause of inherited mental impairment, said a consortium of researchers led by scientists at Baylor College of Medicine in Houston.

Related Articles


Mice deficient in the fragile X mental retardation 1 gene (FMR1) and a similar gene called fragile X-related gene 2 (FXR2) have no rhythm to their wake and sleep pattern, said Dr. David Nelson, professor of molecular and human genetics at BCM and co-director of the Interdepartmental Program in Cell and Molecular Biology.

Normal mice have a sleep-wake cycle of just under 12 hours awake and 12 hours asleep. Exposed to light and dark, they are awake in the dark and asleep during the light because they are nocturnal animals. If they are kept in the dark, their cycle reduces by about 10 minutes per sleep-wake period but remains fairly normal. When mice do not have either FMR1 or FXR2, they have a slightly shorter cycle but the difference is not dramatic.

"However, the double-mutants (those without both genes) have no rhythm at all," said Nelson. "This has never been seen in a mouse before." The animals, usually kept in a cage with a wheel on which they run when awake, sleep a little, run a little, sleep a little -- but there is no rhythm to it.

The finding is important because parents whose children have autism or fragile X report problems getting their children to go to sleep and stay asleep. Fragile X is the most common known cause of autism. While there are few studies on the topic, said Nelson, "the impression I have is that many fragile X patients have a period of time that's like an extended infancy when they don't settle into a typical sleep--wake period."

Understanding how the gene associated with fragile X affect the circadian clock or the sleep-wake cycle could help explain some of the symptoms experienced by patients, he said.

After ruling out the possibility that the animals without the two genes could not perceive light, Nelson collaborated with a group in The Netherlands to test whether the cell's "central clock" called the suprachiasmatic nucleus in the animals was normal. They concluded that the clock was normal but that somehow the expression of genes that govern it is altered in these mice.

"These genes (FMR1 and FXR2) are new players in the control of circadian (daily) rhythms," said Nelson. Currently, the genes are thought to have a role in translating RNAs (ribonucleic acids) -- particularly at the receiving side of the connections between neurons called dendrites. Dendrites are characterized by the fine branches that reach out into tissue. Scientists theorize that FMR1 and FXR2 may be involved in transporting the RNAs to the areas of those branches where the synapse is present.

These findings appeared recently in the American Journal of Human Genetics. Others who took part in this work include Jing Zhang and Zhe Fang of BCM, Corinne Jud and Urs Albrecht of the University of Fribourg in Switzerland, Mariska J. Van Steensel and Johanna H. Meijer of Leiden University Medical Center in The Netherlands, Krista Kaasik and Cheng Chi Lee of The University of Texas Health Science Center at Houston and Ben A. Oostra of Erasmus University Medical Center in Rotterdam, The Netherlands.

Funding for this work came from the U.S. National Institute of Child Health and Human Development, the BCM Mental Retardation and Developmental Disability Research Center, the Fragile X Research (FRAXA) Foundation, the Swiss National Science Foundation and EUCLOCK, a project on the circadian clock sponsored by the European Commission.


Story Source:

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


Cite This Page:

Baylor College of Medicine. "Lack Of Fragile X And Related Gene Fractures Sleep." ScienceDaily. ScienceDaily, 27 June 2008. <www.sciencedaily.com/releases/2008/06/080626125830.htm>.
Baylor College of Medicine. (2008, June 27). Lack Of Fragile X And Related Gene Fractures Sleep. ScienceDaily. Retrieved November 27, 2014 from www.sciencedaily.com/releases/2008/06/080626125830.htm
Baylor College of Medicine. "Lack Of Fragile X And Related Gene Fractures Sleep." ScienceDaily. www.sciencedaily.com/releases/2008/06/080626125830.htm (accessed November 27, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Thursday, November 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Leaves Orphans Alone in Sierra Leone

Ebola Leaves Orphans Alone in Sierra Leone

AFP (Nov. 27, 2014) — The Ebola epidemic sweeping Sierra Leone is having a profound effect on the country's children, many of whom have been left without any family members to support them. Duration: 01:02 Video provided by AFP
Powered by NewsLook.com
Experimental Ebola Vaccine Shows Promise In Human Trial

Experimental Ebola Vaccine Shows Promise In Human Trial

Newsy (Nov. 27, 2014) — A recent test of a prototype Ebola vaccine generated an immune response to the disease in subjects. Video provided by Newsy
Powered by NewsLook.com
Pet Dogs to Be Used in Anti-Ageing Trial

Pet Dogs to Be Used in Anti-Ageing Trial

Reuters - Innovations Video Online (Nov. 26, 2014) — Researchers in the United States are preparing to discover whether a drug commonly used in human organ transplants can extend the lifespan and health quality of pet dogs. Video provided by Reuters
Powered by NewsLook.com
Today's Prostheses Are More Capable Than Ever

Today's Prostheses Are More Capable Than Ever

Newsy (Nov. 26, 2014) — Advances in prosthetics are making replacement body parts stronger and more lifelike than they’ve ever been. Video provided by Newsy
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