Alzheimer's genetic risk is more likely if mother had disease than father, study finds

The likelihood of developing Alzheimer's is higher if your mother had the disease compared to if your father was diagnosed with it, according to new data.

However, the research also indicates that those whose fathers were diagnosed with Alzheimer's before the age of 65 also have a higher than average risk of developing the condition. The study analyzed the amount of amyloid plaques in the brains of 4,400 adults without cognitive impairments, who were on average 70 years old.

The Massachusetts -based research discovered that participants with higher levels of amyloid plaques - protein build-ups thought to precede Alzheimer's - were more likely to have a family history of the disease from their mother's side. It was also found that people whose fathers were diagnosed with Alzheimer's at 65 or younger had higher-than-average amyloid levels in their brains.

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Amyloid plaques are believed to cause Alzheimer's , the most common form of dementia, by accumulating around neurons, disrupting brain cell connections and eventually leading to their death. While Amyloids are naturally-occurring proteins in the body, a specific type known as beta-amyloid can cluster around brain cells, impairing the organ's function.

The accumulation of amyloids can take years to significantly impact mental function. The Massachusetts study's researchers suggested that mitochondria, the minuscule powerhouses within our cells, could be a factor in why patients with dementia mothers are at a higher risk, reports the Mirror .

Mitochondria are inherited from the mother's side, leading researchers to believe there could be a connection. They also theorized that defects in the X chromosome could be responsible, as this is also consistently passed down through the mother.

Fathers with an early-onset form of the disease may have a particularly strong genetic predisposition to Alzheimer's , which could increase their children's risk, according to researchers. "Our study found if participants had a family history on their mother's side, a higher amyloid level was observed," stated study leader Dr Hyun-Sik Yang, a neurologist at Mass General Brigham.

"If your father had early onset symptoms, that is associated with elevated levels in the offspring," added neurologist Dr Mabel Seto, who co-authored the study. The researchers utilized data from the Anti-Amyloid Treatment in Asymptomatic Alzheimer's (A4) study, using brain scans from subjects in the US, Europe, and Japan between April 2014 and December 2017.

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The amyloid levels found were compared with what patients said about their family history with Alzheimer's in order to yield the new results. The participants were not tracked after the study to find out which went on to develop the disease themselves.

As many as 7 million Americans are affected by Alzheimer's disease and it is the 7th leading cause of death in the US. People with a family history of the disease are between two and four times more likely to develop the condition, but the new research is the first to note a difference between whether it is on your mother's or father's side.

An aging population and increasingly unhealthy lifestyles will see case numbers soar to an estimated 12.7 million sufferers by 2050 unless researchers succeed in finding an effective treatment.