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 , 3 , 4 This patient's history is additionally notable for recurrent infections and autistic features, which are other common manifestations of MDS. 5 , 6
FIGURE 1.
EEG of MECP2 duplication syndrome. (A, B) Bipolar and average montage of EEG showing generalized delta slowing and right frontotemporal epileptiform discharges with a broad right hemispheric field (red arrow). (C, D) Bipolar and average montage EEG showing generalized delta slowing and left frontotemporal epileptiform discharges (black arrow).
Test yourself.
- Which EEG pattern can be seen in patients with MECP2 duplication syndrome?
- Normal background activity
- Generalized slowing with focal/multifocal discharges
- Continuous spike‐and‐wave during sleep
- Hypsarrhythmia
- Which of the following is a common comorbidity in MECP2 duplication syndrome?
- Cardiomyopathy
- Recurrent respiratory infections
- Renal failure
- Diabetes mellitus
- What is the inheritance pattern of MECP2 duplication syndrome?
- Autosomal dominant
- Autosomal recessive
- X‐linked recessive
- Mitochondrial
Answers may be found in the supporting information
Supporting information
Data S1.
Data S2.
Otu W, Sudhakaran R, Garza‐Garcia G, Parekh K, Sheikh IS. MECP2 duplication syndrome—Typical EEG characteristics. Epileptic Disord. 2025;27:487–488. 10.1002/epd2.70015
Walter Otu and Ritu Sudhakaran considered as co‐first authors.
Primary investigator/Senior author: Irfan S. Sheikh.
DATA AVAILABILITY STATEMENT
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.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data S1.
Data S2.
Data Availability Statement
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.