Abstracts

Rationale: Unverricht-Lundborg disease, also known as progressive myoclonic epilepsy type 1A (EPM 1), is the most common form of progressive myoclonic epilepsy and is caused by mutations in the CSTB gene encoding cystatin B, a cysteine protease inhibitor. It is inherited in an autosomal recessive pattern and usually caused by expansion of a dodecamer (CCCCGCCCCGCG) repeat or point mutation. EMP1 is characterized by stimulus-sensitive myoclonic seizures, rare generalized tonic-clonic seizures, mild cerebellar syndrome, decline in motor function and variable degree of cognitive impairment. Psychiatric manifestations including depression, mood lability, and anxiety have also been reported. We report a case of Unverricht-Lundborg disease presenting with psychosis.

Methods: A 28-year-old man presented with myoclonic seizures which started at age 14. His seizures were initially well-controlled on valproic acid monotherapy, and patient was seizure-free for over a decade. Unfortunately, his myoclonic seizures recurred at age 25, which became intractable despite trial of multiple anti-seizure medications. Patient since experienced functional decline, psychomotor slowing, and psychosis. Patient reported visual and auditory hallucinations with paranoia. He once hid inside a hotel room due to fear that someone was chasing after him. He was given the diagnosis of possible schizophrenia, and psychotic symptoms were treated with olanzapine with only partial benefit. Subsequent workup included a normal brain MRI, and EEG demonstrating background slowing and generalized high amplitude spike-and-wave and polyspike-and-wave discharges. Genetic testing revealed biallelic expansion in the CSTB gene with more than 30 dodecamer repeats identified. The addition of clobazam led to control of his seizures, and psychotic symptoms subsequently resolved.

Results: Neuropsychiatric manifestations of Unverricht-Lundborg disease have not been systematically studied. Depression has been reported to be the most commonly associated psychiatric symptom, and while degree of depression is typically thought to be mild, severe cases with suicide attempts have been reported. Additionally, emotional lability and anxiety have been described. To our knowledge, this was one of the few reported cases of EPM 1 manifesting as psychosis.

Conclusions: The neuropsychiatric profile of patients with Unverricht-Lundborg disease may be more heterogenous than previously understood. The presence of psychotic symptoms should not preclude the differential diagnosis of Unverricht-Lundborg disease. Future population studies delineating the neuropsychiatric profile of this disease may be of value. This case also highlights the utility of genetic testing in atypical presentations of generalized epilepsy syndromes, which is often underutilized in adult epilepsy patients.

Funding: Please list any funding that was received in support of this abstract.: No funding was received.