20 Feb 2003

At the Society for Neuroscience meeting in San Diego in 2001, Peter Davies first presented saitohin, a minigene nested in the tau gene, and his group’s results have since been published (Conrad et al., 2002). However, as is often the case with AD gene hopefuls, Davies’s early indications that the saitohin polymorphism Q7R is associated with Alzheimer’s are proving hard to confirm in case-control studies of other patient samples. In next month’s Journal of Neurological and Neurosurgical Psychiatry, researchers led by Roger Nitsch and Christoph Hock report that they have not found an association between the reported Q7R polymorphism and Alzheimer’s in their combined Swiss/Greek sample of 225 patients and 144 controls (Streffer et al., 2003).

This report follows on the heels of two other negative studies. Last December, the French Study Group on Alzheimer's Disease and Frontotemporal Dementia checked the distribution of the Q7R polymorphism in 499 AD patients, 91 patients with frontotemporal dementia, and 402 controls. These researchers also saw no link to AD, but did detect a trend toward an association between the QQ genotype and frontotemporal dementia, indicating saitohin might be a factor in tauopathies (Verpillat et al., 2002). Last November, British researchers, including Carol Brayne, also reported finding no link between Q7R and Alzheimer’s (Cook et al., 2002).—Gabrielle Strobel