Study shows Crohn’s and Parkinson’s may share gene mutation

Paul Basilio, MDLinx | February 20, 2018

A new study by an international research collaboration published in Science Translational Medicine identifies a genetic mutation associated with Crohn’s disease.

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Because the mutation leads to functional changes in the coded protein, the probability that a carrier of the mutation will develop the disease is particularly high.

Results of the study showed that people who carry the mutation in the LRRK2 gene are at a high risk of developing the disease. Surprisingly, this mutation had previously been identified as a factor in developing Parkinson’s disease.

“The practical significance is that we can already identify carriers of the gene at a young age and recognize that they are in a risk group and need constant monitoring and adjustment of lifestyle in the hope to lower the chance of disease outbreak,” said Gil Atzmon, PhD, a professor at the University of Haifa, Israel, one of the partners in the study.

Crohn’s disease is particularly prevalent in people between 15 and 30 years of age, as well as in those between 60 and 80 years of age. The reasons for the development of the disease remain unclear, but it may involve a combination of environmental, genetic, and immune factors.

The current study, which involved about 50 researchers from around the world, sought to examine whether mutations of specific genes are more common among people with Crohn’s disease than among those who do not have the disease. The initial examination included 5,700 people of Ashkenazi Jewish origin, who were both Crohn’s disease patients and those without the disease.

Dr. Atzmon explained that the genetic affinity among Ashkenazi Jews makes them a kind of “family” in genetic terms, thereby facilitating the identification of a clear association between genetic mutations and expression of the disease. Moreover, Crohn’s disease is particularly prevalent among Ashkenazi Jews.

After the results were obtained, the researchers examined the genetic association among a much larger group of about 25,000 subjects from around the world.

The findings of the larger study showed that a specific mutation in the LRRK2 gene creates a statistically significant distinction between those with and without Crohn’s disease. The mutation is almost twice as prevalent among Crohn’s patients as among people without it.

Dr. Atzmon suggests that as the mutation leads to functional changes in the coded protein, the probability that a carrier of the mutation will develop the disease is particularly high.

The presence of the mutation in LRRK2 also increases the probability of developing Parkinson’s disease. This is the first similar or associated mechanism identified involving Crohn’s and Parkinson’s.  

“One possibility is that there is no connection, and that this gene is responsible for different and unrelated functions in the body,” Dr. Atzmon said. “Another possibility we examined is that the enhanced expression of an area in this gene encourages phosphorylation, influencing a cascade of events each of which leads in turn to the outbreak of either or both of these diseases.”

The new finding is significant because it will now be possible to administer a relatively simple genetic test to determine whether someone is a carrier of this mutation at a very young age. If they are a carrier, medical monitoring will enable intervention in the early stages of the disease.

Even more importantly, carriers will be able to adjust their lifestyle to reduce drastically the chance of an outbreak of Crohn’s by smoking cessation, reducing stress, and avoiding processed food.

“In the longer time,” Dr. Atzmon said, “the development of a drug that can respond both to the risk of Crohn’s and the risk of Parkinson’s could be a real breakthrough that will be beneficial for large numbers of people.”

To read more about this study, click here

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