Identifying Clues to Parkinson’s Disease

November 12, 2012

Identifying Clues to Parkinson’s Disease

Two new hereditary variants have been identified for Parkinson’s disease, say researchers, and also the role genetics play in this neurodegenerative disorder. Although the causes of Parkinson’s disease remain unknown, environmental and genetic factors are influences. Genetics play a role in a small percentage of cases which affect people who are under the age of 50. This is known as early-onset Parkinson’s. The part genes play in late-onset Parkinson’s is not as well known.

In a new study, published in the journal PLoS Genetics, Nicholas Eriksson, PhD, of the California based 23andMe gene testing company which targets direct to consumer testing, says, “About a dozen genetic associations with Parkinson’s have been confirmed, and many more remain to be discovered. Each new generic variant we find gets us a little closer to being able to see the full picture of how genes impact this disease. Roughly 10 genetic variants that contribute to Parkinson’s had been found and we added another two to the list”. It is estimated that about 25% of the gene variation in susceptibility to developing Parkinson’s disease is because of genetic factors according to Eriksson and colleagues. They also estimate that about a quarter of the variation in susceptibility to the disease is due to genetic factors.

SCARB2 has been recognized as one of the newly identified genetic variants with a known Parkinson’s disease pathway relating to protein degradation.

The other newly identified variant is called SREBF1, and it is not connected with any known Parkinson’s pathway. Do says, “This variant is involved in lipid metabolism. Its association with Parkinson’s is not really clear, which is what makes it exciting because it highlights a new area to look at”.

The researchers have estimated that only about 7% of the genetic variants related to Parkinson’s disease have been identified highlighting the need for more work to identify the remaining 93%.

Eriksson’s colleague Chuong B Do, PhD says “While the genetic variants, or mutations, identified to date explain only a small percentage of Parkinson’s cases, the gene studies have provided clinically relevant information.” He points out that, “One identified mutation is associated with a 50% lifetime risk for developing the disease. This one variant accounts for a very small percentage of the total disease burden, but for people who do have the variant it is quite significant.” he says.

A genome-wide study was carried out by Chuong B Do, PhD and fellow researchers. Involved in this study were 3,400 Parkinson’s patients and almost 30,000 people without the disease who were 23andMe clients. This study took place in an effort to understand genetic influences in both early and late-onset Parkinson’s. Recruitment of the Parkinson’s patients was aided with the assistance of the Michael J Fox Foundation, the Parkinson’s Institute and the National Parkinson’s Foundation. The genetic testing company 23andMe funded this study solely.

The completion of the Human Genome Project allowed the study of genome wide association using the following tools: Computerized human genome sequence database, human genetic variation mapping and also the constantly developing technologies which make it easier to analyze the genetic variations related to Parkinson’s disease.

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