However, another HSA21 gene, DYRK1A can also be considered a candidate causal gene for the pathological changes that occur in the DS and AD brain resulting in the associated cognitive and motor deficits (Ferrer et al., 2005; Wiseman et al., 2015; García-Cerro et al., 2017; Herault et al., 2017; Arbones et al., 2019). The gene discussed is DYRK1A; the disease is Alzheimer disease.