The protein kinase DYRK1A (Dual-specificity tyrosine phosphorylation-regulated kinase 1A), has been found to be a common factor across multiple diseases and to profoundly affect pathology in dementia. The DYRK1A gene is located on chromosome 21.  

DYRK1A is involved in several important processes in the brain, and an overdose/overactivity of this enzyme leads to dementia.