Narrator: This is Science Today. Researchers at the University of California, San Francisco have identified a gene which may be associated with the onset of Alzheimer's Disease. Neurologist Kirk Wilhelmsen, who led the study, found three mutations in a gene which produces tau protein. This has been found to cause several neurodegenerative disorders, including frontotemporal lobe dementia. What's interesting to scientists is that the tau protein has long been a suspected factor in Alzheimer's Disease.

Wilhelmsen: In Alzheimer's Disease, the tau protein clumps up in tangles called neurofibliary tangles and these are a marker that's used to make the diagnosis of Alzheimer's Disease.

Narrator: Before this finding, clumps of tau protein were thought to be a marker of brain cells dying, rather than an actual cause.

Wilhelmsen: We don't think that mutations in the tau gene cause Alzheimer's Disease, but we think that the tau gene is involved in the process that leads to Alzheimer's Disease as well as other diseases and sometimes, the cause is actually a mutation of the tau gene.

Narrator: For Science Today, I'm Larissa Branin.