Beschreibung:
<jats:title>Abstract</jats:title><jats:p>Pathogenic variants in the <jats:italic>SCN8A</jats:italic> gene have been associated with a broad phenotypic spectrum, ranging from benign familial infantile seizures to severe, early‐onset developmental and epileptic encephalopathy. This spectrum also includes an “intermediate phenotype” characterized by different degrees of cognitive disability, mild neurological impairment, and therapeutically manageable epilepsy. We report on a child harbouring a <jats:italic>de novo</jats:italic>, novel <jats:italic>SCN8A</jats:italic> deletion, whose clinical picture is consistent with an <jats:italic>SCN8A</jats:italic>‐related “intermediate phenotype”. This patient's peculiar feature is the occurrence of paroxysmal tonic upgaze (PTU), a non‐epileptic disorder consisting of sustained conjugate upward deviation of the eyes, with neck flexion, and downbeat saccades. PTU has been described in otherwise healthy children, as well as in a few genetic syndromes, but has never been observed in <jats:italic>SCN8A</jats:italic>‐related phenotypes. This report, therefore, adds a new symptom to the spectrum of movement disorders associated with <jats:italic>SCN8A</jats:italic>‐related developmental and epileptic encephalopathy. In this short communication, we provide video‐EEG documentation of PTU and seizures, and discuss the challenging differential diagnosis between the two symptoms.</jats:p>