It is highly unlikely that one-to-one relationships will ever be established between genetic etiologies, electrophysiological abnormalities and clinical epilepsy syndromes, as illustrated by recent identification of GRIN2A mutations, DEPCD5 mutations and 16p11.2 duplications across a number of focal epilepsies and epilepsy aphasia syndromes.32–35 We suggest that ZDHHC9 mutation is associated with susceptibility to focal seizures, but at this point cannot be more precise about the range of electroclinical phenotypes that may be associated with mutations in this gene. Here, ZDHHC9 is linked to focal epilepsy.