Abstracts

Rationale: The neuronal ceroid lipofuscinoses (NCLs) are an heterogenous group of progressive lysosomal storage disorders which can be seen in children and adults. These disorders occur due to intracellular accumulation of an auto fluorescent lipopigment in the neurons and other cells. This accumulation leads to massive neuronal loss and subsequent apoptosis¹. Inheritance is mostly autosomal recessive. Seizures, developmental milestone regression, and impaired vision have been described in these patients. There are multiple clinically distinct types of NCL which are distinguished by the age of onset and genetic cause. The variant late infantile neuronal ceroid lipofuscinosis type 7 is caused by mutations in the CLN7/MFSD8 gene². Electroencephalogram (EEG) findings in this subtype have been poorly described in the literature.

Methods: We conducted an IRB approved retrospective case series of pediatric patients, enrolled in the prospective natural history study at Children Health Dallas, with confirmed genetic diagnosis of CLN7. The case series included analysis of clinical data collected in four patients. Long-term video-EEG studies (23 hours in duration) were obtained in each patient and analyzed by a board certified epileptologist.

Results: 23-hour long-term video-EEG recordings were obtained and analyzed in four patients. All four patients had an abnormal video-EEG. The background activity showed diffuse slowing in the delta and theta range in 75% and 25% of the recordings, respectively. Epileptiform discharges were noted in all patients including independent multifocal spikes (100%) and generalized spike and wave discharges (75%). Seizures were recorded in two patients. In one patient an event was triggered by photic stimulation and described as a focal motor (myoclonic) seizure with concomitant spike and wave activity seen in the bioccipital regions. The second patient had an unprovoked atonic seizure with a generalized ictal correlate.

Conclusions: Electroencephalogram (EEG) findings in variant late infantile neuronal ceroid lipofuscinosis type 7 (CLN7) have been poorly described in the literature. We report a case series of four patients where long-term video-EEG was obtained. EEG findings were non-specific and consistent with a multifocal and/or generalized encephalopathy with high risk for seizures. Two seizures were captured identified as a myoclonic and an atonic seizure. Ictal EEG showed a bioccipital non-lateralizing onset triggered by photic stimulation and a generalized onset, respectively. Further studies are needed to reach a more conclusive description on electro-clinical patterns of patients with CLN7.

Funding: Please list any funding that was received in support of this abstract.: N/A.