Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Multiple Sclerosis in genetically susceptible twins is augmented by the northern environment

11.08.2006
A new study of twins suggests that living farther north of the equator significantly increases risk of developing Multiple Sclerosis (MS) among those with genetic susceptibility due to some environmental factor.

By following more than 700 pairs of twins diagnosed with MS, researchers from the Keck School of Medicine of the University of Southern California found that people born in the north tended to come to physicians for diagnosis slightly earlier than those born farther south, and that the tendency for identical twins to both be diagnosed was greater in those born in the north.

The concordance (both twins being diagnosed with MS) among identical twin pairs born in the north was nearly twice as high as among those born elsewhere (18.6 % vs. 9.5%). There was significantly less concordance among fraternal twins. The results were published in the in the July issue of Annals of Neurology.

Locations categorized as "northern" included Canada or states at or above 42 degrees north, including Alaska, Oregon, Washington, Idaho, Montana, Nebraska, North Dakota, South Dakota, Wyoming, Michigan, Minnesota, Wisconsin, Connecticut, Maine, Massachusetts, New Hampshire, New York, Rhode Island and Vermont.

Twins were divided into two categories, either monozygotic (identical twins with the same genetic makeup, coming from one egg) or dizygotic (fraternal twins, coming from two separate eggs). An effect that is seen more commonly in the monozygotic twins suggests a heavier role is being played by genes.

"We've known that MS is more common the farther away from the equator you get," says Thomas Mack, professor of preventive medicine at the Keck School of Medicine of USC and lead author of the study. "By looking at the number of times this occurs in twins – both identical and fraternal twins – we could see whether it was just a matter of latitude or if there is something else. This study suggests there's more concordance among identical twins, which means there is some environmental exposure and it is interacting with the genes."

If environment alone was responsible for the increased incidence of both members of the twin pair getting MS, there would be similarly high concordance among fraternal twins. The study did not suggest that, however, showing instead that both identical twins were far more likely to get the disease than both fraternal twins.

In fact, despite clear evidence of a much higher incidence of MS among women, the study found high concordance in both male and female identical twins, implying that mechanisms of inheritance are probably identical by sex. In other words, genetic susceptibility trumps the traditional bias against MS in most males.

Northern residence also contributed significantly to earlier onset of the disease. The researchers suggest that an early onset in the North could represent an early environmental deficit in protection, such as by less opportunity for early exposure to the sun, or for unknown reasons to an unrecognized causal factor, such as a virus. "It may even be that exposure to the sun interrupts whatever effect a virus has," Mack says.

Kathleen O'Neil | EurekAlert!
Further information:
http://www.usc.edu

More articles from Studies and Analyses:

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>