08:49pm Thursday 27 February 2020

Gene Predicts Risk for Alzheimer’s Disease Symptoms after Traumatic Brain Injury, Penn Study Finds

PHILADELPHIA – The presence of a gene can predict when a traumatic brain injury (TBI) will lead to early symptoms of Alzheimer’s disease, according to a new study from neuroscientists at the University of Pennsylvania School of Medicine. Amyloid plaque deposits, known primarily for their role in Alzheimer’s disease, are found in nearly one third of people who die from acute TBI, within just hours of a brain injury and in people of all ages. This build up of Alzheimer’s-like deposits can be predicted by a variation in the gene that codes for the amyloid-busting enzyme, neprilsyin.

A single traumatic brain injury (TBI) has emerged as an important risk factor for the later development of Alzheimer’s disease. While plaques in Alzheimer’s disease develop slowly over time and almost exclusively in the elderly, the same pathology can be found rapidly following TBI.

“These findings may be very important for individuals at high risk of TBI, such as participants in contact sports or military personnel,” said senior author Douglas Smith, MD, director of the Penn Center for Brain Injury and Repair and professor of Neurosurgery at the University of Pennsylvania School of Medicine. “A genetic screening tool may be useful in identifying those at risk of developing Alzheimer’s-like amyloid plaques following a traumatic brain injury.”

The amyoid-degrading protein, neprilysin, has been found in abundance following TBI. Variations in an individual’s ability to produce effective neprilsyin may explain why some people generate plaques while others do not.

Researchers looked at genetic samples from 81 head-injured victims who had died acutely following brain trauma between 4 hours and 25 days following their injuries. As expected, in around a third of cases, amyloid deposits were found throughout the brain, similar to what is seen in early Alzheimer’s patients. Researchers found that variations, known as polymorphisms, in part of the neprilysin gene correlated strongly with the presence of these plaques. The study appeared in the Journal of Neurotrauma.

Future studies may investigate whether these genetically predisposed individuals are the same people who go on to develop Alzheimer’s disease after TBI.


PENN Medicine is a $3.6 billion enterprise dedicated to the related missions of medical education, biomedical research, and excellence in patient care. PENN Medicine consists of the University of Pennsylvania School of Medicine (founded in 1765 as the nation’s first medical school) and the University of Pennsylvania Health System.

Penn’s School of Medicine is currently ranked #3 in the nation in U.S.News & World Report’s survey of top research-oriented medical schools; and, according to the National Institutes of Health, received over $366 million in NIH grants (excluding contracts) in the 2008 fiscal year. Supporting 1,700 fulltime faculty and 700 students, the School of Medicine is recognized worldwide for its superior education and training of the next generation of physician-scientists and leaders of academic medicine.

The University of Pennsylvania Health System (UPHS) includes its flagship hospital, the Hospital of the University of Pennsylvania, rated one of the nation’s top ten “Honor Roll” hospitals by U.S.News & World Report; Pennsylvania Hospital, the nation’s first hospital; and Penn Presbyterian Medical Center, named one of the nation’s “100 Top Hospitals” for cardiovascular care by Thomson Reuters. In addition UPHS includes a primary-care provider network; a faculty practice plan; home care, hospice, and nursing home; three multispecialty satellite facilities; as well as the Penn Medicine at Rittenhouse campus, which offers comprehensive inpatient rehabilitation facilities and outpatient services in multiple specialties.

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