According to a study published in Nature on Dec. 11, 2013, variations in a gene called phospholipase D3 (PLD3) may double the risk of developing late-onset Alzheimer’s disease (AD). This gene may be useful as a novel therapeutic target for treating AD.
Alzheimer’s disease is an irreversible, progressive brain disease that slowly destroys memory and thinking skills. There are an estimated 70,000 people living with Alzheimer's disease in Connecticut (5.2 million in the United States). In 2012, family and friends provided 200 million hours of unpaid care to those with Alzheimer’s and dementia – care valued at $2.5 million (nationwide, 15.4 million family and friends provided $216.4 billion of unpaid care to those with Alzheimer’s and dementia). For more on Alzheimer’s disease, see the video at left and the photos in the slideshow above left.
Thus far, identifying genes with a significant effect on Alzheimer’s risk and a clear functional role has been difficult. The few gene variants that have been identified only have small effects on the risk of late-onset AD. Using whole-exome sequencing (a technique that focuses only on the portions of DNA that form messenger RNA, or exons), this recent study identified a rare variant in the PLD3 gene that significantly increases the risk for late-onset AD. Additional follow-up tests in large populations of African and European descent suggest that other variants in this gene also increase risk.
The study found that higher levels of PLD3 resulted in reduced amyloid-beta (amyloid-beta is typically elevated in Alzheimer’s disease patients). In contrast, lower levels of PLD3 increased amyloid-beta. The study also found lower levels of PLD3 in brain tissue from patients diagnosed with Alzheimer’s disease than from cognitively normal individuals. These results indicate that the PLD3 gene influences the production of amyloid-beta.
In summary, this study found that PLD3 is an AD risk gene (variants in this gene increase the risk for AD) and plays a role in the processing of amyloid-beta. These results suggest that PLD3 could be a new potential therapeutic target for the treatment of Alzheimer’s disease.
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