Minibrain/DYRK1A-gene: Candidate gene for mental retardation in Down syndrome?

DYRK1A is the first member of a novel subfamily of protein kinases with dua l specificity. The human gene for DYRK1A is located in the "Down syndrome c ritical region" (21q22.2). Due to its relationship to the Drosophila gene m inibrain (Mnb), whose mutation results in specific defects in neurogenesis, and based on functional experiments on transgenic mice, DYRK1A is discusse d as a candidate gene for mental retardation in Down syndrome. The kinase i s characterized by its ability to catalyze tyrosine-directed autophosphoryl ation as well as phosphorylation of serine/threonine residues in substrates . Its exact cellular function is yet unknown. DYRK1A is, however, known to be translocated into the nucleus and supposed to be involved in the control of cell growth and development. The pathogenetic impact of DYRK1A on Down syndrome needs further elucidation.