Although the hallmark symptoms of Parkinson’s disease (PD) – such as involuntary shaking, slowness of movement and muscle rigidity – are related to movement, recent evidence has suggested that memory impairment plays an outsized role in diminished quality of life and the burden placed on caregivers.
A new study finds that mutations in the gene for glucocerebrosidase (GBA), known to be a risk factor for PD, also have a powerful influence on the development of cognitive decline. The study was published in Annals of Neurology, the journal of the American Neurological Association.
Two defective copies of the GBA gene are known to cause Gaucher’s disease, a childhood disorder that causes death by age two or severe neurologic complications. One defective copy of the gene was once thought to be of little consequence, but has recently emerged as a common risk factor for Parkinson’s disease.
The new report examined 2,304 patients from the US, Canada and Europe, finding that 10 percent carried one (or more) defects in copies of the GBA gene. Patients carrying one defective GBA gene copy had an increased risk of memory troubles. This effect was most troublesome for patients carrying a GBA copy with the most severe type of defect — known as a neuropathic GBA mutation — whose risk of developing cognitive decline over time was increased by 217 percent. Approximately half of the carriers of a neuropathic GBA mutation developed global cognitive impairment within ten years of being diagnosed with Parkinson’s. Among the PD patients without a mutation, only about 20 percent developed this decline in cognitive function.
Therapies for Gaucher disease have been available since 1994. The researchers hope that their findings will open the door for a completely new type of clinical trials in Parkinson’s — GBA-directed trials designed to proactively prevent memory troubles in patients with movement-related symptoms.
Paper: “Specifically neuropathic Gaucher’s mutations accelerate cognitive decline in Parkinson’s”
Reprinted from materials provided by Brigham and Women’s Hospital.