Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Association between famine and schizophrenia may yield clues about inherited diseases and conditions

03.08.2006
The higher risk of schizophrenia among offspring of expectant mothers living through famine could help us understand the genetic basis for that debilitating mental disorder, a group of researchers argue in a commentary piece in the Aug. 2 issue of JAMA. The finding also supports a theory of medical genetics in which diseases and conditions can be caused by hundreds of different genetic mutations in any number of human genes.

Epidemiologists have studied two major famines in the 20th century: the Dutch Hunger Winter of 1944-45, which was brought about by the Nazi occupation in World War II; and the Chinese famine in 1959-61, a consequence of the failed Great Leap Forward. During both famines, birth rates dropped precipitously. In addition, among children born to women who were pregnant during the famine, the incidence of schizophrenia increased two-fold.

The expectant mothers were not receiving enough folate and other vital micronutrients during the famine, researchers believe, and that deficiency caused new genetic mutations to appear at exceptionally high rates. New mutations in genes related to brain function could lead to development of schizophrenia

"Folate has a major role in genetic processes -- gene transcription and regulation, DNA replication, and the repair of damaged genetic information," explained co-author Dr. Jack McClellan, an associate professor of psychiatry at the University of Washington and medical director of the Child Study and Treatment Center in Tacoma, Wash. "If folate is missing from a mother's diet, that could lead to genetic mutations in the developing fetus."

Nearly three-quarters of the human body's 20,000 or so genes are involved in the development or functioning of the brain in some way, and about one-fourth are specifically brain-related genes -- leaving many possible locations where new genetic mutations would affect the brain. Since schizophrenia has its genesis in the development and distribution of neurons, McClellan said, the areas of the genome related to those processes are probably where researchers will find disease-related mutations.

In addition to urging future research in this area, McClellan and his co-authors, Dr. Ezra Susser of Columbia University and Dr. Mary-Claire King, the American Cancer Society Professor of Medical Genetics and Genome Sciences at the UW, argue that schizophrenia is the latest in a string of disorders showing the nature of inheritance of genetic conditions. The conventional wisdom on psychiatric disorders is that most cases are caused by a handful of common genetic mutations that occur in a small number of genes.

"The problem with that model is that it doesn't correspond to clinical experience," said King. "Studies of families with many complex diseases, like breast cancer, epilepsy, or inherited hearing loss, indicate that many different genetic mutations in many different genes can lead to each disease."

Researchers jokingly refer to this hypothesis as the Anna Karenina model of medical genetics -- each unhealthy family is unhealthy in its own way.

This alterative model of genetics helps explain other aspects of schizophrenia as well. In nearly all populations, the disease has a fairly stable rate of incidence. But in populations with maternal famine, that rate increases significantly. If there are many different possible mutations that could cause schizophrenia, and the number of mutations in a population goes up (due to malnutrition, for example), then one would expect the rate of the disease to rise, as it did during the two famine events.

In addition, schizophrenia can affect the rate of reproduction in people with the condition -- they often have difficulty developing and maintaining relationships with others, so tend to have smaller families and fewer children than other people. If only a small number of common genetic mutations were responsible for schizophrenia, scientists would expect them to become less and less common over time, as people with the condition had fewer children who would carry on those mutations. Instead, the risk of schizophrenia has stayed at about the same level, suggesting that new genetic mutations may crop up periodically to cause the illness anew.

Schizophrenia does run in families, but most people with the condition do not have close relatives with schizophrenia. For many schizophrenia patients, their illness seems to come from out of the blue. This pattern also suggests that new, different mutations appear in different families, McClellan said, and may continue for a few generations before dying out. That could make it hard to determine which genetic mutations cause the disease.

"Normally, if you're looking for what causes an illness, you gather everyone with that illness together and look for mutations they share," said McClellan. "That may be why it has been so hard to find the genetic basis for schizophrenia. The cause may be different from one case to another."

Justin Reedy | EurekAlert!
Further information:
http://www.washington.edu

More articles from Health and Medicine:

nachricht Penn vet research identifies new target for taming Ebola
12.01.2017 | University of Pennsylvania

nachricht The strange double life of Dab2
10.01.2017 | University of Miami Miller School of Medicine

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>