In a later study that quantified the levels of several NGF pathway proteins (proNGF, neuroserpin, tissue plasminogen activator (tPA), and metalloproteases) in samples from AD-asymptomatic DS (n = 14), prodromal AD (n = 10) DS, AD dementia (n = 12), and controls (n = 16), ProNGF and MMP-3 levels were elevated, while tPA was decreased in plasma in individuals with DS. This evidence concerns the gene MMP3 and Alzheimer disease.