<scp>MECP2</scp> duplication syndrome—Typical <scp>EEG</scp> characteristics

We report a 36-year-old male with a history of psychomotor and intellectual delay, right hemiparesis, and seizures since age 17 controlled on valproic acid, felbamate, and rufinamide. Chromosomal microarray performed at age 28 revealed a copy number gain of chromosome band Xq28 (3.273 Mb in size), including the MECP2 gene, consistent with MECP2 duplication syndrome (MDS).1 EEG demonstrated a poorly organized background with generalized delta slowing and bilateral independent frontotemporal interictal epileptiform discharges (Figure 1). EEG findings in patients with MDS can be consistent with generalized delta slowing and interictal findings of generalized slow spike-andand-wave asynchronous discharges with frontotemporal predominance. Additional EEG findings can include interictal sharp and slow wave discharges with frontotemporal predominance and generalized paroxysmal fast activity (GPFA).2-4 This patient's history is additionally notable for recurrent infections and autistic features, which are other common manifestations of MDS.5, 6 The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions. Data S1. Data S2. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. Which EEG pattern can be seen in patients with MECP2 duplication syndrome? Which of the following is a common comorbidity in MECP2 duplication syndrome? What is the inheritance pattern of MECP2 duplication syndrome? Answers may be found in the supporting information