You may be more likely to develop Alzheimer’s disease if your mother has been diagnosed with the disease, compared to if your father suffered from it, a new study suggests.
However, those whose parents have been diagnosed early with the degenerative disease (before age 65) may be at higher risk of developing the disease earlier than the average patient.
Massachusetts researchers made the discovery after analyzing brain scans of 4,400 adults with an average age of 70 and no cognitive decline.
Each brain was scanned for amyloid plaques, a toxic protein buildup thought to be a precursor to Alzheimer’s, the most common form of dementia.
The researchers found that those with higher levels of plaques in the brain tended to have a family history of the disease on their mother’s side.
You may be more likely to develop dementia if your mother had the disease at some point in her life, study suggests
However, higher than average amyloid levels were also seen in the brains of those whose parents were diagnosed with Alzheimer’s at age 65 or younger.
Amyloid plaques are thought to trigger the disease by disrupting communications between brain cells, preventing the organ from functioning properly.
They build up silently over time and can remain in the brain for years before any symptoms of the disease occur.
The researchers suggested that patients whose mothers had dementia might be at higher risk because of specific mitochondria, tiny structures in cells that produce energy.
These are only inherited from the mother but carry their own DNA, including mutations that may predispose them to not function properly.
The researchers also theorized that the risk could have to do with faults in the X chromosome, which is always passed from parents to children.
Parents can also pass on an X chromosome, making their offspring female; however, this only occurs in 50 percent of newborns.
Dr. Hyun-Sik Yang, a neurologist at Mass General Brigham who led the research, said, “Our study found that if participants had a family history on their mother’s side, a higher level of amyloid was seen.”
“If your father had early-onset symptoms, that is associated with elevated levels in the offspring,” added neurologist Dr. Mabel Seto, who also participated in the study.
The graph above shows the positive and negative percentage of amyloid plaques.
Alzheimer’s disease affects about 7 million Americans and is the seventh leading cause of death in the United States.
The condition is believed to be a largely hereditary disease: studies show that between 60 and 80 percent of patients have a family history.
Those who have a parent or relative with the disease are thought to be between two and 15 times more likely to develop the disease, depending on the number of affected relatives.
Previous studies have also found that the maternal line may have more impact than the paternal line in transmitting diseases.
Among the celebrities who have revealed a history of Alzheimer’s in their family is Peter Gallagher, who cared for his mother while she suffered from the disease for two decades.
She previously said: “An Alzheimer’s diagnosis can be as devastating for the caregiver as it is for the person diagnosed.”
For the latest article, published today in JAMA NeurologyThe researchers extracted data from the Anti-Amyloid Treatment in Asymptomatic Alzheimer’s study (A4).
This involved scanning the brains of adults at sites in the US, Europe and Japan between April 2014 and December 2017 for amyloid plaques.
The patients were mostly of non-white ethnic backgrounds, the researchers said, which may have affected the results.
The adults were not followed for years after the study, so it was unclear how many actually developed dementia.
Although amyloid plaques are the main hypothesis for the cause of dementia, others suggest that their role is less important, pointing instead to damage to blood vessels as the main cause.
The number of adults with Alzheimer’s disease in the U.S. is expected to increase to 12.7 million by 2050 due to an aging population and increasingly unhealthy lifestyles.
The disease usually begins in the mid-70s, although in rare cases it can occur between the ages of 40 and 50.
Symptoms begin as difficulty remembering recent events or conversations, repeated questions, or trouble remembering where you left things.
In later stages, the disease causes loss of awareness of surroundings, inability to communicate coherently, and difficulty swallowing or eating.