What Causes AD? The Tau Hypothesis

Contributed by: Michael Rafii, M.D., Ph.D - Director of the Memory Disorders Clinic at the University of California, San Diego.

This is the third blog in my series about the causes of AD.

While the Amyloid hypothesis has been in favor in recent years, buildup of amyloid plaques does not correlate well with the loss of brain cells. As such, scientists have restlessly searched for alternative explanations.

One such explanation is the tau hypothesis, encompassing the idea that tau protein abnormalities initiate the disease cascade. According to this theory tau proteins pair with other threads of tau and form damaging tangles inside nerve cells. When this occurs, the cell's transport systems disintegrate and malfunction which may disrupt communications between cells and later cause cell death.

One tau-based treatment (Rember) is planned for FDA phase III clinical trials this year.


  1. Do other countries have the same rate of Alzheimer's as we do? I never see press coverage of French of Italian people having this problem. Are they doing something better than we are, or is it the same there?

  2. Actually, Alzheimer's disease is a worldwide problem with patients affected everywhere. Interestingly, certain countries have fewer citizens who have the disease. For example, Sweden, India and Japan have some of the lowest rates. We believe this is due in part due to dietary differences, as well as genetic differences. France and Italy are closer to the United States with regards to incidence of Alzhiemer's disease.

  3. My mother's AD went undiagnosed (at 87 years of age)although she frequently saw her internist and other physicians.Low salt levels seems to sharply increase her decline, but she wasn't given medication--only told to eat more salty foods. Her gait and balance were major symptoms that caused her to fall several times. She always reported that she was fine and went on with her life. Why isn't an AD evaluation made a standard procedure for patients at 80 years? I think that this could have helped our family understand and better provide for her needs.. and prevented her from being in auto accidents etc. Pearl's best Friend--rhonda