Genetic Variant Accelerates Cognitive Decline in Parkinson’s

the Psychiatry Advisor take:

Having a certain genetic variant can influence the rate of cognitive decline in patients with Parkinson’s disease.

Ignacio F. Mata, PhD, of Veterans Affairs Puget Sound Health Care System, Seattle, Washington, and colleagues examined 1,079 Parkinson’s disease patients who underwent several tests analyzing memory and cognitive function. Participants also underwent testing to determine the presence of alleles, or genetic mutations, in certain genes that play a role in cognition.

Parkinson’s disease patients with the ε4 allele in the apolipoprotein E (APOE) gene had lower scores on assessments of memory and attention, as well as executive and cognitive function, the researchers reported in JAMA Neurology. Variants of two other genes, MAPT and SNCA, were not associated with scores on the tests.

Prior research has indicated the ε4 allele is associated with moderating the level of beta-amyloid, a plaque found in the brains of those who suffer from neurocognitive diseases.

The latest findings comes on the heels of a study published in JAMA Psychiatry last month that found that the genotype of the APOE gene does not impact the accuracy of beta-amyloid levels as a biomarker for Alzheimer’s disease.

“Among [Parkinson’s] patients without dementia, the APOE ε4 allele was only associated with lower performance on word list learning and semantic verbal fluency, a pattern more typical of the cognitive deficits seen in early Alzheimer’s disease than [Parkinson’s],” the researchers concluded.