Interestingly, a phenotype rescue experiment crossing Ts65Dn mice, which have three copies of Dyrk1a, with mice monosomic for a 33-gene chromosomal segment containing Dyrk1a (Ms1Rhr) produced progeny with a normal learning phenotype, indicating that triplication of this 33-gene region is necessary to produce the cognitive deficit (Belichenko et al., 2009). Here, DYRK1A is linked to Cognitive impairment.