Genetic Parkinson’s More Common Than Thought, Global Survey Reveals

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by Alice Melão |

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Cases of inherited Parkinson’s disease may be more frequent than previously reported, results from an online global survey suggest.

The survey, which was conducted by members of The Michael J. Fox Foundation Global Genetic Parkinson’s Study Group (MJFF-GGPSG), also revealed the willingness of investigators to share clinical information on their patients that could be useful to conduct broader and more inclusive studies.

These findings suggest it is necessary to improve the way investigators communicate and assess clinical data. It also highlights the need of new integrative research approaches that can empower teams to enhance the understanding and recognition of genetic mutations contributing to the development of Parkinson’s disease. This could be an important step to improve early diagnosis and define preventive strategies.

The results, “Identifying genetic Parkinson’s disease patients worldwide: Exploiting novel ways of team science,” were presented as a scientific poster during the International Congress of Parkinson’s Disease and Movement Disorders in Nice, France.

“This initiative is of high relevance because it is becoming increasingly clear that even relatively common diseases like Parkinson’s disease are highly etiologically heterogeneous syndromes and that progress towards early diagnosis and causative treatments will depend on the identification of sufficient numbers of well-defined subgroups,” Thomas Gasser, MD, said in a press release. Gasser is director of the department of neurodegeneration at Hertie Institute for Clinical Brain Research, in Tuebingen, Germany.

“This will only be possible by collaborations at a very large, preferably worldwide scale,” he said.

The survey, which was conducted in 2018, was designed to evaluate the availability of demographic, clinical, genetic, and additional data of patients with genetic Parkinson’s disease. It included cases caused by SNCA, LRRK2, VPS35, PRKN, PINK1, PARK7, and GBA mutations.

MJFF-GGPSG researchers addressed the survey to 336 investigators who were selected based on articles that had been published about the subject and were represented at the Movement Disorder Society Genetic mutation database (MDSGene), and through the Genetic Epidemiology of Parkinson’s disease (GEoPD) consortium.

Of the 336 investigators invited to participate in the survey, 162 (48%) responded, 98% of whom indicated interest in further collaboration.

“The overwhelmingly positive response and willingness to collaborate impressively highlight the relevance and power of team science,” the researchers wrote.

Researchers reported information from a total of 8,453 Parkinson’s patients with genetic mutations; more than nine different ethnicities were followed at 103 international sites across 43 countries.

Overall, mutations in the SNCA, VPS35, PINK1, and PARK7 genes were present in 3% (263 patients), 0.4% (35 patients), 3% (260 patients) and 0.3% (29 patients) of this patient population.

The most commonly affected genes were LRRK2, GBA, and PRKN, with mutations present in 38% (3,182 patients), 37% (3,154 patients), and 18% (1,530 patients).

These frequencies are particularly significant given that they represent a threefold higher number of patients with mutations associated with Parkinson’s disease when compared to the cases reported in the literature.

More than 98% of investigators who responded to the survey noted they had demographic data on their patients, with 94% of them having age-at-onset information, and only 66% reported having information on patients’ non-motor signs.

Most investigators (85%) had DNA samples from the patients, while only 8% had cerebrospinal fluid (CSF) samples. (CSF is the liquid that surrounds the brain and spinal cord.)

“This survey is only a very first small step. If international team science is to become successful, many problems concerning standardization of patient ascertainment, data privacy and protection as well as data access and use need to be solved,” Gasser said.

“Nevertheless, the survey raises awareness of these issues and it clearly shows that the Parkinson’s disease research community is ready to begin to tackle these important issues,” he said.