Molecular cytogenetic characterization of an interstitial deletion of chromosome 21 (21q22.13q22.3) in a patient with dysmorphic features, intellectual disability and severe generalized epilepsy

► A child with intellectual disability and epilepsy is reported. ► Array CGH showed an interstitial deletion of 4.9 Mb from 21q22.13 to 21q22.3. ► Patients with the same deletion manifest a strikingly similar phenotype. ► Two genes, DYRK1 and KCNJ6, seem to play a major role in this phenotype.