COVID-19 updates for our patients and visitors Learn More


Dr. Leon Thal, Renowned Alzheimer's Expert, Dies in Plane Crash


February 05, 2007  |  

Leon Thal, M.D., Distinguished Professor and Chair  of Neurosciences at the University of California, San Diego (UCSD) School of Medicine, and one of the world’s leaders in the development and study of new therapies for Alzheimer’s disease, has been killed in a plane crash that occurred Saturday night, February 3.  Thal, 62, was piloting the plane between San Diego and Borrego Springs, California.  Cause of the crash is unknown at this time.

Thal was director of the UC San Diego Shiley-Marcos Alzheimer’s

Dr. Leon Thal, M.D.
Disease Research Center, and has been director of the multi-center Alzheimer’s Disease Cooperative Study (ADCS) since it was first established in 1991.  He was also on staff at the Veterans Affairs San Diego Healthcare System.


“It is with deep regret and sadness that we learned of this tragic accident,” said UC San Diego Chancellor Marye Anne Fox.  “Dr. Thal’s contributions to his field and to this university are innumerable and invaluable.  He was a valued and loved member of the UCSD family.  Our thoughts are with his family, friends and colleagues during this difficult time.”

“In my view, a view shared by many, Leon Thal was the most prominent scientist in the world in the field of Alzheimer’s disease,” said David N. Bailey, UC San Diego Interim Vice Chancellor for Health Sciences and Dean, School of Medicine.  “He was an exceptional physician and teacher, a man with brilliant insights and extraordinary creativity.  This is a devastating loss on many levels, professionally and personally.”

Thal’s entire career has been devoted to the study of aging and dementia.  Over the past three decades, he achieved a remarkable body of research productivity that includes more than 300 peer-reviewed papers.  One of the world’s leading investigators engaged in development of new therapies for Alzheimer’s disease, his efforts contributed significantly to the world’s understanding of the cause, prevention and treatment of AD and related disorders.  He directed more than $100 million in federally funded research grants, and was a collaborator on many others.

In recognition of his career accomplishments and leadership in the field of Alzheimer’s research, he was awarded The Potamkin Prize, one of the nation’s highest honors in neurosciences, in 2004.   In presenting the award, the American Academy of Neurology recognized Thal’s “outstanding achievements in research of Alzheimer’s and related neurodegenerative diseases.”

“We have lost one of the giants at UCSD and in the world of Alzheimer’s disease research,” said Patrick Lyden, M.D., vice-chair of the Department of Neurosciences and Chair of the School of Medicine Faculty Council.  “This is a moment of incredible shock and inexpressible sadness. I know I speak for many colleagues when I say that Leon Thal is truly irreplaceable. And I have lost a leader, mentor and friend. He was an internationally recognized authority in Alzheimer’s, having led pioneering breakthroughs in drug therapy for patients. He led the UCSD Department of Neurosciences for over a decade, during which time our Department grew exponentially. Personally, Dr. Thal mentored all of us with humor and candor, and recruited several top young researchers in Alzheimer’s, Parkinson’s, multiple sclerosis, and stroke to San Diego.”

"This is a catastrophic loss, for us personally and for the world.  Leon is the reason we first started giving in support of Alzheimer's disease.  He was a great guy, someone you could pick up the phone and talk to and feel enlightened, and at the same time, feel that you've just talked to a friend," said Darlene Shiley who, along with husband Donald Shiley, has been a generous donor to Alzheimer's disease research, including a $4 million gift to support UCSD's Alzheimer's Disease Research Center.  The UCSD center is named the Shiley-Marcos Alzheimer's Center in recognition of the gift, and to honor Darlene's mother, Dee Marcos, whose Alzheimer’s disease was first diagnosed by Dr. Thal.

"Professor Thal bridged the gap between clinical medicine and basic neuroscience in a remarkably successful way.  He brought together some of the most talented investigators in the field of neurodegenerative disease and helped to push the reputation of the Department of Neurosciences at UCSD to the highest level in its 40-year history,” said Henry Powell, professor of pathology and Chair of the UC San Diego Academic Senate. “Aside from his intellectual gifts, he was a skillful manager of strong-minded people, charming and diplomatic as well as visionary and persuasive.  I think all of us who knew him well felt enriched by the friendship he shared so easily with us.  In the shock of loss our thoughts are with his wife, with the patients he cared for and with the teams of clinicians and investigators who looked to his leadership every day.  This is a huge blow to UCSD."

As director of the ADCS, Thal led a consortium of more than 70 research centers around the United States and Canada.  Established to test drugs for their effectiveness in slowing down the progression or treating the symptoms of AD, as well as to investigate new methods for conducting dementia research, the ADCS was recently awarded $52 million by the National Institute on Aging to continue its work.  More than 4,600 people have participated in these studies.

He was recently named to the Alzheimer's Association’s National Board of Directors, and was appointed in 2004 by Governor Arnold Schwarzenegger to serve on the Independent Citizens Oversight Committee of the California Institute for Regenerative Medicine.  He also served on the National Institute on Aging Advisory Council.  He was a frequent reviewer and consultant for the National Institutes of Health as well as the National Science Foundation and Veterans Administration.  He served on the editorial boards of numerous professional journals.

Thal was born in New York, NY.  He earned his M.D. degree at Downstate Medical Center in New York and completed residency and fellowship training at Albert Einstein College of Medicine, where he continued on the faculty until his recruitment to UC San Diego as an Associate Professor in 1985.  He also served for several years as Chief of Neurology at the Veterans Affairs San Diego Healthcare System.  He became Chair of the Department of Neurosciences at UC San Diego in 1993.  He also held the Florence Riford Endowed Chair in Alzheimer’s Disease at UC San Diego.

He is survived by his wife, Donna Thal, Ph.D., a distinguished professor emeritus of San Diego State University.  Plans for memorial services are pending.  Friends and colleagues may send contributions in lieu of flowers to a charity of the giver’s choice.

Media Contact: Debra Kain, 619-543-6163,

Media Contact

Share This Article

Related News

UC San Diego Health’s gastroenterology endoscopy program has been recognized as a leader in quality and safety by the American Society for Gastrointestinal Endoscopy (ASGE), the leading national gastr ...
The new UC San Diego Shiley EyeMobile for Children is driving to schools in San Diego County to serve low-income families in need of eye exams. The EyeMobile, a program of UC San Diego Health, will vi ...
UC San Diego School of Medicine study shows cannabis-related emergency department visits among older adults are on the rise with high risk for adverse effects of cannabis use for ages 65 and older.
UC San Diego Health is the only institution in the region to receive grant funding from the California Department of Health Care Access and Information to provide support for underrepresented high sch ...

Follow Us