One hallmark of Alzheimer's disease is the presence in patients' cerebrospinal fluid of high levels of a protein called tau, and of a specific phosphorylated version of tau known as ptau181. Researchers have now linked a variant of a gene that is involved in tau modification to faster progression of the neurodegenerative disease.

Carlos Cruchaga at Washington University in St. Louis, Missouri, and his co-workers screened hundreds of spinal-fluid samples for 384 variants of 34 tau-related genes. They teased out one, rs1868402, that was associated with ptau181 levels. In another group of 259 patients, the researchers found that those carrying the version of rs1868402 associated with high ptau181 levels had clinical symptoms that worsened twice as fast as average, and six times faster than those with the variant linked to low ptau181 levels.

PLoS Genet. 6, e1001101 (2010)