Scientists Identify a New Parkinson’s Disease Gene

Science News

- May 20 2015

By studying the genes of a large family in which eight members across two generations were affected by Parkinson’s disease (PD), researchers have identified a new genetic mutation that may cause PD. The results appear in the March edition of The Lancet Neurology.

Most people with Parkinson's have “sporadic” disease. This means the exact cause is unknown, and their disease is likely to be a combination of underlying genetic predisposition and environmental exposures. Scientists have discovered some two dozen genetic mutations in which such changes may increase a person’s risk of devoping Parkinson's disease.

For the new study, researchers led by Nobutaka Hattori, M.D., at Juntendo University School of Medicine in Tokyo, Japan, analyzed DNA from members of a large family in which eight members across two generations were diagnosed with PD. Using a combination of techniques, they identified a mutation that was a likely cause of their PD. Then, taking advantage of a DNA bank, the researchers searched for this mutation in genetic material in more than 1,400 other individuals: 341 with familial PD, 517 with sporadic PD, and 559 healthy individuals.

Results

• Members of the first family the researchers studied carried a mutation, or change, within the gene known as CHCHD2.
• By screening samples in the DNA bank of people with familial PD, the scientists identified three additional families with CHCHD2 mutations passed down through two generations. One of these families had the same mutation first identified; the other two families had different mutations in the CHCHD2 gene.
• The two families with the same mutation were likely not related.

What Does It Mean?

The field of the genetics of PD dramatically developed in the past couple decades, with scientists discovering more than 20 genes linked to PD. Despite these discoveries, it is likely that there are many more genes linked to PD risk, that have not yet been discovered.

In this study, scientists from Japan implicated a new gene, CHCHD2, in PD risk. Although the mutation that was identified within CHCHD2 seems a likely cause of PD, scientists will need to confirm this result by finding the same genetic change in additional families with many cases of PD, ideally from different ethnic backgrounds. The study authors also suggest that variations in the CHCHD2 gene may increase PD risk without causing it directly.

In the population of people with PD, very few are likely to have PD that is linked to CHCHD2 mutations. Yet the discovery of genetic changes associated with PD remains critical to helping scientists to understand PD overall. The reason for this lies in the fact that every gene is responsible for making a protein, and proteins are the molecules that do work inside cells. By finding genetic changes associated with PD, researchers gain insight into the network of protein interactions that underlie the disease. In some cases, fairly common genetic changes that increase PD risk act on the same molecular pathways as rare mutations.

Ultimately, the hope is that understanding what goes awry at the molecular level to cause PD will lead to strategies for new therapies.

Learn More

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Reference: Funayama, M., Ohe, K., Amo, T., Furuya, N., Yamaguchi, J., Saiki, S., et al. (2015). CHCHD2 mutations in autosomal dominant late-onset Parkinson's disease: a genome-wide linkage and sequencing study. Lancet Neurology, 14(3), 274–282. http://doi.org/10.1016/S1474-4422(14)70266-2
http://dx.doi.org/10.1016/S1474-4422(14)70266-2

Source Date: May 20 2015