A higher-than-expected prevalence of gene mutations in Parkinson’s disease patients suggests genetic testing should be offered to them more broadly, researchers said in the medical journal Brain.

Genetic profiling performed on more than 8,000 patients of varying races and ethnicities, all with Parkinson's disease, showed 13% had a genetic form of the progressive brain disorder, the researchers found.

That rate was 18% in patients with known risk factors, such as earlier age at onset, Parkinson’s disease in a first-degree relative or certain ancestry such as Ashkenazi Jewish, Spanish Basque or North African Berber.

Among patients with no known risk factors, more than 9% had a predisposing genetic mutation.

With new gene-specific drugs for the disease entering the research pipeline, the implications of the findings are significant, the researchers said.

Previous studies had suggested that about 5% to 10% of Parkinson’s disease cases were linked with genetic variants - and most of those studies had been limited to patients with known risk factors.

Presently, only a small fraction of people with Parkinson’s disease receive genetic testing, largely because neurologists are uncomfortable with their knowledge of Parkinson’s disease genetics, access to genetic counselors is limited and the identification of a genetic basis has been unlikely to impact a patient’s treatment, said James Beck, senior vice president and chief scientific officer of the Parkinson’s Foundation, the study’s sponsor.

But with recent advances, doctors "are now on the cusp of figuring out how to treat patients based on genetics," Beck said.

With trials of gene-specific treatments underway, and genetic results potentially impacting disease prognosis and shedding light on familial risks, clinical genetic testing should be offered to everyone with Parkinson’s disease, the research team concluded.