Featured Research

from universities, journals, and other organizations

Fragile X gene's prevalence suggests broader health risk

Date:
June 14, 2012
Source:
University of Wisconsin-Madison
Summary:
The first US population prevalence study of mutations in the gene that causes fragile X syndrome, the most common inherited form of intellectual disability, suggests the mutation in the gene -- and its associated health risks -- may be more common than previously believed.

The first U.S. population prevalence study of mutations in the gene that causes fragile X syndrome, the most common inherited form of intellectual disability, suggests the mutation in the gene -- and its associated health risks -- may be more common than previously believed.

Writing this month (June 2012) in the American Journal of Medical Genetics, a team of Wisconsin researchers reports that the cascade of genetic amino acid repeats, which accumulate over generations and culminate in the mutation of a single gene causing fragile X, is occurring with more frequency among Americans than previously believed. The study also shows that as the genetic basis for the condition is passed from generation to generation and amplified, risks to neurological and reproductive health emerge in many carriers.

"The premutation of this condition is much more prevalent than we previously thought and there are some clinical risks associated with that," explains Marsha Mailick Seltzer, director of the University of Wisconsin-Madison Waisman Center, who led the new study.

Fragile X is caused by the unexplained runaway expansion of a set of amino acid repeats in a single X chromosome gene known as FMR1. When fully mutated, the gene fails to express and produce a protein that's required for healthy brain development. The syndrome, which is more common in boys, results in a spectrum of intellectual disability.

However, before the gene fully mutates, carriers of the faulty gene exhibit a smaller number of elevated repeats, which expand as the gene is passed from generation to generation. Normal FMR1 genes exhibit anywhere from five to 40 repeats. Carriers with a premutation may have anywhere from 55 to 200. Those with between 45 and 54 repeats are characterized as falling into a "gray zone." Carriers of gray zone expansions often pass the mutation on to their children who themselves are at greater risk of having the premutation, and in subsequent generations the risk of a full mutation causing fragile X syndrome is high.

The goal of the new study was to calculate the prevalence in a U.S. population of the premutation and the gray zone. The research was based on data from the Wisconsin Longitudinal Study (WLS), also known as the "Happy Days study," which for more than 50 years has tracked the careers, family life, health and education of more than 10,000 graduates of Wisconsin's high school class of 1957.

Using genetic samples from 6,747 WLS participants, the team led by Seltzer, an expert on developmental disability and family life, found that 1 in 151 females and 1 in 468 males carry the fragile X premutation while 1 in 35 females and 1 of every 42 males fall into the gray zone.

"The prevalence is high, the second highest reported in the world literature," says Seltzer, noting that the incidence of fragile X varies by population and is higher in some places such as Israel, and lower in others like Asia.

The expansion of the FMR1 gene is known to vary across ethnic groups. The sample in the WLS study is primarily white and of northern European descent.

People with the premutation are more likely to have a child with disability; to have neurological symptoms such as numbness, dizziness and faintness; and, for women, to experience early menopause. Although these symptoms have been recognized previously in clinical studies, the WLS data represent an unbiased sample and supports those observations.

"This study confirms that there are health risks associated with the premutation," says Seltzer. "People with the premutation have a higher probability of neurological and reproductive problems. There is a significant public health burden."

The new Wisconsin study was supported by the U.S. Centers for Disease Control. Co-authors include Mei Wang Baker of the Wisconsin State Laboratory of Hygiene; Jinkuk Hong, Matthew Maenner and Jan Greenberg, all of UW-Madison's Waisman Center; and Daniel Mandel of the Centers for Disease Control.


Story Source:

The above story is based on materials provided by University of Wisconsin-Madison. The original article was written by Terry Devitt. Note: Materials may be edited for content and length.


Journal Reference:

  1. Marsha Mailick Seltzer, Mei Wang Baker, Jinkuk Hong, Matthew Maenner, Jan Greenberg, Daniel Mandel. Prevalence of CGG expansions of the FMR1 gene in a US population-based sample. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics, 2012; 159B (5): 589 DOI: 10.1002/ajmg.b.32065

Cite This Page:

University of Wisconsin-Madison. "Fragile X gene's prevalence suggests broader health risk." ScienceDaily. ScienceDaily, 14 June 2012. <www.sciencedaily.com/releases/2012/06/120614131105.htm>.
University of Wisconsin-Madison. (2012, June 14). Fragile X gene's prevalence suggests broader health risk. ScienceDaily. Retrieved July 26, 2014 from www.sciencedaily.com/releases/2012/06/120614131105.htm
University of Wisconsin-Madison. "Fragile X gene's prevalence suggests broader health risk." ScienceDaily. www.sciencedaily.com/releases/2012/06/120614131105.htm (accessed July 26, 2014).

Share This




More Health & Medicine News

Saturday, July 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

AFP (July 24, 2014) A so-called drugs rehab 'clinic' is closed down in Pakistan after police find scores of ‘patients’ chained up alleging serial abuse. Duration 03:05 Video provided by AFP
Powered by NewsLook.com
Too Few Teens Receiving HPV Vaccination, CDC Says

Too Few Teens Receiving HPV Vaccination, CDC Says

Newsy (July 24, 2014) The Centers for Disease Control and Prevention is blaming doctors for the low number of children being vaccinated for HPV. Video provided by Newsy
Powered by NewsLook.com
New Painkiller Designed To Discourage Abuse: Will It Work?

New Painkiller Designed To Discourage Abuse: Will It Work?

Newsy (July 24, 2014) The FDA approved Targiniq ER on Wednesday, a painkiller designed to keep users from abusing it. Like any new medication, however, it has doubters. Video provided by Newsy
Powered by NewsLook.com
Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Newsy (July 24, 2014) Sheik Umar Khan has treated many of the people infected in the Ebola outbreak, and now he's become one of them. 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:
from the past week

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