Absence of BRCA1 Gene is responsible of Alzheimer’s and Breast Cancer

When BRCA1 levels were reduced in mice, researchers saw DNA damage and brain shrinkage.

In normal individuals, gene BRCA1 is responsible for preventing cancer and repairing DNA.

A gene linked to both breast and ovarian cancer also appears to play a role in Alzheimer’s, a new study shows.

When one or both of the strands breaks, DNA repair proteins – including BRCA1 – work to fix the strands so that the cell does not die. BRCA1 plays a key role in repairing deoxyribonucleic acid (DNA), our genetic code. That’s the gene mutation that led actor/director Jolie to opt for a preventive mastectomy two years ago and, earlier this year, have her ovaries and fallopian tubes removed.

Since Alzheimer’s patients also show similar symptoms, the study results made scientists wonder whether lack of BRCA1 protein leads to cognitive impairment in such patients. The researchers wanted to figure out of this protein has a hand in the BRCA1 depletion. Mucke found that in the case of breast cancers, some changes can trigger tumors’ growth. The researchers concluded their findings in the journal Nature Communications, after observing that the levels of BRCA1 gene are also reduced in patients with Alzheimer’s disease.

It is not known if people with the BRCA1 mutation are more likely to develop Alzheimer’s disease.

“By normalising the levels or function of BRCA1, it may be possible to protect neurons from excessive DNA damage and prevent the many detrimental processes it can set in motion”.

Dr Lennart Mucke, the study’s lead author and director of the Gladstone Institute of Neurological Disease and a professor of neurology at the University of California, San Francisco, said: ‘It’s extremely interesting that one molecule can be critically involved in two apparently opposing conditions: cancer, in which too many cells are born and neurodegenerative disease, in which too many cells die off’. Amyloid beta, a protein, has always been associated with Alzheimer’s disease.

The Gladstone Institutes are ascertaining if memory loss or cognitive decline can be prevented by an increase in BRCA1 levels. This suggests that the protein helps to keep the brain healthy – and that a drug which restores its levels to normal could halt, and even prevent, Alzheimer’s.

“Additional studies are needed to address these possibilities and explore the therapeutic potential of enhancing DNA fix in Alzheimer’s disease and related conditions”, the study said.

There are no current treatments to boost proteins from the BRCA1 gene.

To do so, the researchers analyzed neuronal BRCA1 levels in post-mortem Alzheimer’s patient brains, comparing the findings with those taken from healthy tissue.

To test this theory, the scientists reduced BRCA1 levels in neurons in laboratory mice.

‘This study supports and strengthens that theme by showing that beta-amyloid decreases the level of the DNA fix gene BRCA1, and at the same time inhibits the ability to form new memories’. So, mice with low BRCA1 developed cognitive problems.