Myoclonic Encephalopathy In Non-progressive Disorders

Etiologies: Half of the children have chromosomal abnormalities (such as Angelman syndrome, Prader Willi syndrome, Wolf-Hirschhorn syndrome and Ring 20 (r20) syndrome). In addition, gene mutations (such as MECP2), brain structural abnormalities (developmental abnormalities or acquired damage) and metabolic causes (such as non ketotic hyperglycinemia) can also be caused, and about 1 / 5 of them have unknown etiology [1-4].

Age of onset: onset of seizures from day 1 of life to 5 years (peak 12 months).

Seizure characteristics: The incidence rate of female is about 2 times that of male, often with myoclonic status epilepticus, with intermittent absence seizures and may have focal motor seizures.

EEG: Interictal: background is typically abnormal with slow activity seen, accompanied by frequent focal or multifocal slow waves and spikes wave. Ictal: EEG shows transient bursts of continuous or nearly continuous slow spike-and-wave discharges, and myoclonic jerks may not correlate with EEG findings [3-4].

Brain MRI: Structural or acquired brain abnormalities may be found.

Developmental progress: developmental delay.

Reference

1. Kim, H.J., et al., Genetic and epileptic features in Rett syndrome. Yonsei Med J, 2012. 53(3): p. 495-500.
2. Pelc, K., et al., Epilepsy in Angelman syndrome. Seizure, 2008. 17(3): p. 211-7.
3. Panayiotopoulos.  癫痫综合征及临床治疗.  北京 : 人民卫生出版社, 2012.
4. 刘晓燕.  临床脑电图学. 第2版.  北京 : 人民卫生出版社, 2017.