Mucopolysaccharidosis type II or Hunter syndrome (MPS II) is a genetic disease that can course with intellectual impairment and central nervous system (CNS) alterations. To date, no report has documented electroencephalogram (EEG) measures associated with CNS alterations, detected by imaging studies, and the history of seizures in patients with MPS II. Therefore, we decided to search this association. We included 9 patients with MPS II and performed imaging studies of the brain to detect the presence of cortico-subcortical atrophy, enlarged subarachnoid space and supratentorial ventricular size. Additionally, we performed EEG studies in sleep and awake conditions and a complete clinical description. Five out of the nine patients presented history of seizures and all except one patient (88.9%) presented some CNS structural alteration in the imaging studies, being the most frequent the cortico-subcortical atrophy (77.8%). The EEG results showed low amplitude in all patients and low voltage in sleep condition in eight patients with interhemispheric asymmetry in six patients during awake and sleep conditions. Although the five patients with history of seizures did not present a distinctive EEG anomaly, four of them presented some structural alteration in the imaging studies. In conclusion, most patients presented structural alterations in the CNS; likewise, all of them presented EEG anomalies mainly during sleep conditions. However, a clear association between EEG, CNS and the history of seizures was not established.
Keywords: Electroencephalogram; Hunter syndrome; Magnetic resonance imaging; Mucopolysaccharidosis type II.