APP and Down syndrome: Most interestingly, PLAT was found to be down-regulated 3.3 fold (p = 0.0037) in the brains of Down's syndrome patients (see supplemental information published in [25]), who also have a greater prevalence of strokes [26] and in which Aβ42 levels are increased due to a gene dosage effect caused by triplication of the APP gene localized on chromosome 21 (trisomy 21).