Parkinson’s risk low for most with Gaucher type 1, new study finds
Fewer than 15% with most common disease type diagnosed by age 80
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People with Gaucher disease type 1 are known to be at increased risk of Parkinson’s disease, but data from a new study show that fewer than 15% of those with this disease type — marked by an absence of neurological symptoms — will develop Parkinson’s in their lifetime.
The findings suggest that almost 1 of every 8 people with Gaucher type 1 (about 12%) will receive a diagnosis of Parkinson’s, a progressive neurological disease, by the time they reach age 80. About 1 in 5, or approximately 20%, will show signs consistent with Parkinson’s-like conditions, the data show.
Overall, “most patients remain free of [Parkinson’s disease],” the researchers wrote.
The study, titled “Age-Specific Parkinson Disease Risk in Gaucher Disease Type 1 Data From the ICGG Gaucher Registry,” and covering patients primarily from European nations and the U.S. and Canada, was published in the journal Neurology.
A genetic disorder, Gaucher is caused by mutations in the GBA1 gene. Gaucher type 1, the only form of the disease that does not affect the brain or spinal cord, is the most common type and also the mildest one, with patients generally achieving a near-normal life expectancy with modern treatments.
Parkinson’s, meanwhile, is a neurological disorder known particularly for its motor symptoms, which include tremor, abnormally slow movement, and rigidity. People with Parkinson’s also may experience cognitive problems, as well as balance issues and constipation.
Investigating the actual risk of Parkinson’s in Gaucher type 1
It’s well established that individuals with Gaucher type 1 have a greater risk of developing Parkinson’s relative to people in the general population. However, it hasn’t been clear exactly how many people with this disease type will actually develop Parkinson’s in their lifetime.
To address this question, an international team of scientists combed through data from the International Collaborative Gaucher Group Gaucher Registry (NCT00358943), a global registry collecting long-term health data on people with the disease who are being followed at hundreds of sites worldwide. The registry is funded by Sanofi, and several of the authors of this study are employees of the company.
The analysis involved data from 1,618 people with Gaucher disease type 1. The researchers used statistical tests to calculate how many patients had a diagnosis of Parkinson’s at various ages, noting that this analysis is “the most comprehensive assessment of age-specific [Parkinson’s disease] risk in a [Gaucher disease type 1] population to date.”
The results showed that 4% of Gaucher patients had been diagnosed with Parkinson’s by age 60. By age 80, 12.2% had a formal diagnosis of Parkinson’s.
“For context, the risk of [Parkinson’s disease] in the general population is approximately 1% by age 60 years and 4% by age 80 years,” the researchers wrote.
To account for the fact that some patients might have Parkinson’s despite not having a formal diagnosis, the researchers also looked at the number of individuals with possible Parkinson’s. This included everyone with a formal diagnosis of Parkinson’s or a related neurological disease called dementia with Lewy bodies (DLB), as well as individuals who displayed at least two signs or symptoms commonly found in people with Parkinson’s.
Using this broader definition, 6% of patients had possible Parkinson’s by age 60 and 23% by age 80, according to the researchers.
Overall, given the data from this large patient group, the team wrote: “We estimate that approximately 12% [of people with Gaucher type 1] will develop [Parkinson’s] by age 80.”
Researchers call for neurological assessments of older patients
In Gaucher, some disease-causing mutations cause the GBA1 gene to be completely nonfunctional, whereas others only slightly decrease the gene’s activity. Further analyses indicated that patients with milder mutations were generally less likely to have definite or possible Parkinson’s. The risk of Parkinson’s was also lower in women compared with men, though this difference wasn’t statistically significant.
The researchers noted that the data used in this study mostly came from patients from North America and Europe. As such, “generalizability to other regions is unknown,” the team wrote.
These findings have important implications for patient counseling, screening strategies, and early intervention, particularly for motor symptoms, which appeared earlier than other clinical features, and may allow for timely diagnosis and management.
Still, these new data may help inform genetic counseling for individual patients, the scientists noted. More broadly, the results underscore the need for routine neurological assessments in aging people with Gaucher type 1, so that those who do develop Parkinson’s can be appropriately diagnosed and receive timely care, according to the team.
“These findings have important implications for patient counseling, screening strategies, and early intervention, particularly for motor symptoms, which appeared earlier than other clinical features, and may allow for timely diagnosis and management,” the researchers wrote.
The team also noted a need for further studies to better determine why only some people with Gaucher type 1 develop Parkinson’s.
“Understanding these modifiers could ultimately pave the way for targeted neuroprotective strategies, benefitting both [Gaucher disease type 1] and broader [Parkinson’s disease] populations,” the scientists concluded.
Overall, the team wrote, “future studies should move toward greater diagnostic clarity through the systematic screening of all patients by movement disorder specialists.”
