Much is being discovered about the genetic origins of Alzheimer's disease, but it is still considered to be caused by a combination of genetic and environmental factors, and generally not a primarily heritable condition. A new study is suggesting the genetic impact of the disease could be more significant than previously thought, finding a strong link between the ages of parents and children for the onset of the disease.

The study, led by Sylvia Villeneuve from McGill University, found that the closer a person gets to the age their parent displayed the first signs of Alzheimer's disease, the more likely they were to have a build-up of amyloid plaques in their brain.

"A 60-year-old whose mother developed Alzheimer's at age 63 would be more likely to have amyloid plaques in their brain than a 70-year-old whose mother developed the disease at age 85," explains Villeneuve.

The results of the study were duplicated in two separate cohorts, consisting of over 250 subjects altogether, and interestingly, were more prominent in women than men.

"Upon examining changes in the amyloid biomarker in the cerebrospinal fluid samples from our subjects, we noticed that this link between parental age and amyloid deposits is stronger in women than in men," says Villeneuve. "The link is also stronger in carriers of the ApoE4 gene, the so-called 'Alzheimer's gene'."

It is worth noting the study is small and does not follow whether these amyloid plaque deposits in the younger generation did lead to an actual onset of Alzheimer's. But early identification is key in trying to manage the devastating condition and this research could help identify those at risk by suggesting parental history is much more of an important factor than previously imagined.

The research was published in the journal JAMA Neurology.