Three cases with deletion of the whole sodium channel gene cluster (SCN3A, SCN2A, SCN1A, SCN9A, and SCN7A) exhibited a complex epilepsy phenotype that was atypical for Dravet syndrome and suggestive of migrating partial seizures of infancy: early seizure onset (before 2 months of age), severe developmental delay from seizure onset, multifocal interictal spikes, polymorphous focal seizures, and acquired microcephaly.
C0424605
Developmental delay (disorder)