Genetics can influence a person's risk of developing Alzheimer's disease, and new research indicates that this risk varies depending on which parent had the illness. In a study involving 4,400 cognitively unimpaired individuals, those whose mother or both parents had Alzheimer's showed higher levels of amyloid protein plaques in their brains, a key indicator of Alzheimer's. This was in contrast to individuals whose fathers had the disease.

The research team from Mass General Brigham in Boston found that people with an Alzheimer's-affected mother might be at special risk. "Maternal inheritance of Alzheimer’s disease may be an important factor in identifying asymptomatic individuals for ongoing and future prevention trials," said Dr. Reisa Sperling, a neurologist at Mass General and study co-author. The findings were published on June 17 in JAMA Neurology.

The study utilized data from a clinical trial focused on Alzheimer's prevention. Participants were asked if either of their parents had been diagnosed with Alzheimer's and when their parent's memory issues began. Sperling and her colleagues then compared these responses to amyloid levels in the participants' brains.

The results indicated that having a father who developed Alzheimer's later in life did not correlate with higher amyloid levels. However, there was a clear link between brain plaque accumulation and having a mother with Alzheimer's, regardless of when her symptoms began. Additionally, having a father with early-onset Alzheimer's was associated with elevated amyloid levels in the offspring.

Dr. Mabel Seto, the study's first author and a postdoctoral research fellow in neurology at the hospital, explained, "If your father had early-onset symptoms, that is associated with elevated amyloid levels in the offspring. However, it doesn’t matter when your mother started developing symptoms -- if she did at all, it’s associated with elevated amyloid."

The sex of the study participant did not affect the relationship between amyloid buildup and parental history, the researchers noted. They also highlighted that most participants were non-Hispanic white, suggesting that the findings might differ in other racial and ethnic groups.

This study underscores the importance of considering parental history, particularly maternal history, when assessing Alzheimer's risk and designing prevention strategies.