A case of Poirier-Bienvenu neurodevelopmental syndrome with non-epileptic seizures, phonophobia, and autism spectrum disorder

Poirier-Bienvenu neurodevelopmental syndrome (POBINDS) is caused by mutations in CSNK2B and is characterized by intellectual disability (ID) and early-onset epilepsy. The patient was delivered at term with no perinatal complications. Although early development was typical, delayed walking prompted a referral. Various screening tests identified no physical or laboratory abnormalities, except for traits of autism spectrum disorder (ASD). At approximately three years of age, the patient began experiencing recurrent episodes of unresponsiveness, characterized by a vacant stare. Ictal electroencephalography (EEG) revealed right temporal spike waves spreading bilaterally, leading to a diagnosis of focal onset epileptic seizures. During the same period, paroxysmal twitch-like and gross-like movements were observed. These movements occurred without epileptic discharges, leading to a diagnosis of non-epileptic seizures (NES). The patient was diagnosed with ASD based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria. Subsequently, it was noted that the patient exhibited twitch-like and gross-like movements with fearful facial expressions when watching specific television programs, accompanied by phonophobia. These episodes were considered psychogenic NES (PNES), likely attributable to auditory hypersensitivity associated with ASD. The NES episodes resolved with avoidance of these television programs. At nine years of age, next-generation sequencing identified a heterozygous CSNK2B mutation, confirming the diagnosis of POBINDS. Focal onset epileptic seizures were well controlled with valproic acid and clobazam. This case highlights a patient with POBINDS presenting with ASD and NES due to sound hypersensitivity. The coexistence of epileptic seizures and NES in individuals with POBINDS warrants further investigation.