HIPK2 and Dystonia: Zhang et al.8 observed that Hipk2−/− mutants show a severe psychomotor behavioral phenotype that reflects neuronal deficiencies in the substantia nigra pars compacta and the ventral tegmental area,9 and we (personal and unpublished observations) noticed that Hipk2 knockout mice show behavioral abnormalities consistent with cerebellar defects, such as dystonia, impaired coordination, reduced motility, and clasping of posterior limbs.8 Thus, on the basis of these observations, we investigated whether Hipk2 is involved in cerebellar functions.