Proschel et al. (97) overexpressed either wild-type or 4 different mutant SIK1 isoforms [as described in Hansen et al. (95)] in human primary fetal cortical neurons and showed that epilepsy-causing mutations in SIK1 were associated with decreased MEF2C protein and transcriptional activity, and decreases in the length and number of neurites. The gene discussed is MEF2C; the disease is epilepsy.