TDP-43 is also a major disease protein in another neurodegenerative condition known as frontotemporal dementia (FTD).
Recently mutations in the gene that codes for the TDP-43 protein (known as TARDBP) have been discovered in individuals with ALS and have been shown to account for approximately 2-6% of all familial ALS cases. The discovery of mutations in the TARDBP gene implies that the accumulation of abnormal TDP-43 protein alone may be sufficient to cause ALS and suggests that TDP-43 could serve as a biomarker for sporadic ALS.
A recent study has shown that TDP-43 protein can be detected in blood samples and that levels of the protein are elevated in some patients with Alzheimer disease and FTD. Two other small studies in Germany and Japan detected TDP-43 in cerebral spinal fluid (CSF) and found increased levels of TDP-43 in some patients with sporadic ALS. These findings suggest that TDP-43 protein can be detected in bodily fluids such as blood and CSF and may lead to the discovery of a diagnostic test for both ALS and some forms of FTD.
