Idiopathic recurrent stupor caused by benzodiazepine or endodiazepine (episodes are shorter and not associated with derealization), metabolic encephalopathies, for example, those with hyperammonemia such as mild cases of ornithine transcarbamylase deficiency (but patients present with protein intolerance, intense vomiting, and gastrointestinal symptoms not seen in KLS; further, the EEG is also abnormal). Here, OTC is linked to hyperinsulinemic hypoglycemia, familial, 4.