Several studies have previously identified pathogenic STXBP1 SNVs [55,56,57,58], as well as partial or whole gene deletions [55,59] in patients with developmental and epileptic encephalopathy 4 (OMIM # 612164), overlapping with the symptoms—intellectual disability, global developmental delay, seizures and multifocal epileptiform discharges—seen in our patient. This evidence concerns the gene STXBP1 and early-infantile DEE.