DYRK1A and Down syndrome: DYRK1A syndrome, also known as DYRK1A haploinsufficiency syndrome and Intellectual developmental disorder, autosomal dominant 7 (MRD7) (OMIM:614104) is generally caused by the presence of a pathogenic variant of DYRK1A, that reduces the functional copy number of DYRK1A from two to one, and likely decreases DYRK1A protein levels (Arranz et al., 2019).