Cerebrospinal fluid tau and amyloid beta42 protein in patients with myotonic dystrophy type 1.

BACKGROUND: Myotonic dystrophy type 1 (DM1) is associated with brain morphology changes including neurofibrillary degeneration. METHODS: We have examined cerebrospinal fluid (CSF) markers indicative of neuronal degeneration and amyloidogenesis; total tau (T-tau), phosphorylated tau (P-tau) and beta amyloid 1-42 (Abeta42), in 32 patients with DM1. RESULTS AND CONCLUSIONS: Associations between CSF markers and CTG repeat expansion size, brain MRI findings, and neuropsychological test results were analysed. As compared with matched controls Abeta42 was significantly decreased (P = 0.001), whilst levels of T-tau were increased (P < 0.001). No difference was found between measures considering P-tau levels. At present the clinical implications of these findings is unclear, because of an overlap between CSF values of DM1 patients and healthy controls, but also regarding modest associations between CSF markers and other measures. However notably, the Tau pathology, as seen in DM1, differs from Alzheimers disease, considering the lack of increased levels of P-tau.