Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Genetic testing for Parkinson disease, is there a point?

07.12.2005


Should we start being genetically tested for Parkinson’s disease (PD)? According to research just published in the December issue of the "journal Movement Disorders" this might be a possibility in the future if you belong to a family affected by G2019S, a genetic mutation responsible for some PD cases.



Parkinson disease results from the death or loss of function of the nervous cells (neurons) in a brain area called substancia nigra, which is involved in the regulation of movement. Neurons within this region produce dopamine, a neurotransmitter that acts as messenger between the substancia nigra (the control centre) and other neurons around the body, leading to a correct regulation of the body movements. If the substancia nigra degenerates, like it happens in PD, dopamine is no longer properly produced and the individual starts presenting the typical symptoms of Parkinson’s disease such as slowed movements, tremors, loss of movement control and rigidity.

Although there is still no cure, treatments, which increase the brain’s dopamine levels, are relatively effective. Unfortunately, as disease progresses, treatment becomes less and less efficient and the patient’s full deterioration is inevitable. The disease affects about 1% of the world population with, only in the US, half a million people affected and about 50,000 new cases are reported every year, a number predicted to increase as the average age of the populations also increases.


In fact, among the risks factors for PD, advanced age is the most important with more than 3% of the population above 65 years old affected. In a society where life expectancy has been increasing consistently, especially in the developed world, this situation can lead to major health and economic problems emphasising the urgency to understand better the disease.

Additionally, environmental factors also seem to have an important role in the regulation of PD although which factors, is still not clear. But it is believed that toxins, slowly accumulated over time, can induce disease. One example of this effect was the observation that MPTP (a by-product of synthetic heroin), which in the 80s was sold in the streets by mistake, was able to induce severe end stage parkinsonian symptoms in several young drug abusers as result of specific destruction of the substancia nigra, as later found by autopsy. Another example is the observation that PD incidence is much higher in rural areas what have led researchers to propose that toxins in herbicides or pesticides may cause or contribute to the disease. Interestingly, both caffeine consumption and smoking seem to diminish disease incidence.

Furthermore, individuals with a family history of PD also have a higher chance of suffering from the disease. Indeed, although for a long time favoured as an environmental triggered disease, in the last decade researchers have identified several (five so far) genes, which when mutated can lead to PD.

Nevertheless, until very recently the number and importance of the cases resulting from genetic mutations was considered too low to be relevant in the overall disease panorama. This idea only started to change with the last discovered gene, LRRK2. In fact, LRRK2 mutations seem be particularly frequent accounting for 3 -6% of PD familial cases (when the mutation in inherited and so found within families in more than one individual) and around 2% of PD sporadic cases (when the mutation occurs occasionally in a random and isolated manner). These high numbers have led to a series of studies investigating the gene and its mutations in order to understand better the epidemiological importance of LRRK2.

José Miguel Bras, Rita João Guerreiro, Andrew Singleton and colleagues from Portugal and the USA decided to investigate, in a Portuguese group of 128 patients and 1400 healthy individuals, what they previously found to be the two most common LRRK2 mutations. They discovered that while one of the mutations could not be found among their patients, the other, called G2019S, was found in a remarkably high number of individuals - about 6% of the total number of patients. Very interestingly, it was also found that all the individuals with G2019S suffered from disease, while none of the healthy controls had the mutation. This suggests that G2019S is a pathogenic mutation, meaning that when it occurs in an individual it will always result in disease, in contrast with other mutations where only a fraction of the affected individuals will suffer from the illness. This conclusion was supported by previous research by the same scientists, which showed the same disease pattern in two American families with G2019S, and again a total absence of the mutation in more than 1500 healthy controls this time from the US.

Guerreiro, Singleton and colleagues’ work is important not only because it helps to understand better the dynamics of PD, but because it raises the issue of genetic testing for Parkinson’s disease among G2019S affected families or even high-risk populations. In fact, not only G2019S seems to be present in a high number of PD patients, but also is a pathogenic mutation that will lead to disease sooner or later. Genetic testing of a non-curable fatal disease is not an easy option but, although there is still no cure for Parkinson’s disease, early diagnosis and consequent treatment might result in a longer healthier life and in this sense might be a wise, even if difficult, choice for patients

Piece researched and written by: Catarina Amorim (catarina.amorim@linacre.ox.ac.uk)

Catarina Amorim | alfa
Further information:
http://www.linacre.ox.ac.uk
http://www3.interscience.wiley.com/cgi-bin/abstract/111090322/ABSTRACT

More articles from Life Sciences:

nachricht Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory

nachricht How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>