Besides age, the biggest risk factor for developing Alzheimer’s disease is having a parent or other first-degree relative with the condition. A new study adds to growing evidence that inheriting it from your mother is much worse than inheriting it from your father.
Researchers at the University of Kansas School of Medicine recruited 21 adult children (age 63 to 83) of Alzheimer’s patients who were still “cognitively intact.” They examined their brains using an MRI scanner on two occasions, two years apart. Then they compared those brain scans with those of 32 other healthy adults in the same age group with no family history of Alzheimer’s. Members of both groups had similar levels of education and cognitive performance.
Though none of the subjects exhibited any outward signs of dementia, the brain scans revealed that the 11 people whose mothers had Alzheimer’s had lost significantly more gray matter over the 2-year period than the 10 people whose fathers had the disease and compared with the 32 people with two healthy parents. That cell loss was especially pronounced in two areas of the brain – the left precuneus (which plays a role in episodic memory, among other functions) and the left parahippocampas gyrus (which is involved in encoding and retrieving memories).
Other regions that took a hit were “the anterior cingulate, the bilateral middle temporal gyrus, the right hippocampus, right precuneus, and posterior cingulate,” according to a study in the March 1 edition of the journal Neurology.
The brains of those whose fathers had Alzheimer’s disease were essentially the same as those of subjects with no family history. Only having a mother with the disease appeared to influence the degree of brain atrophy.
The researchers said they don’t know why Alzheimer’s appears to be more aggressive when inherited from one’s mother instead of one’s father. Perhaps it’s related to mitochondrial DNA, which is inherited only from one’s mother and which may be responsible for faulty glucose metabolism in brain tissue affected by Alzheimer’s, they wrote.