CSNK1E and neurodevelopmental disorder: These regions include the 5’UTR and intron 1 of the epilepsy candidate gene CSNK1E, the 5’UTR of the neurodevelopmental disorder gene DIP2B, and the 5’UTR of the uncharacterized gene BCLAF3. We report the occurrence of hypermethylation, a CGG repeat expansion, and reduced expression of CSNK1E among three unrelated individuals with uDEEs and a mildly affected mother.