Clinical and genetic characteristics of developmental and epileptic encephalopathy caused by SLC1A2 gene mutations
10.3760/cma.j.cn115354-20240908-00550
- VernacularTitle:SLC1A2基因突变致发育性癫痫性脑病的临床及遗传学特点分析
- Author:
Lin WANG
1
;
Junxia LUO
;
Yujie GUO
;
Yehong CHEN
;
Xiuli ZHAN
;
Zaifen GAO
Author Information
1. 山东大学附属儿童医院（济南市儿童医院）癫痫中心，济南 250022
- Keywords:
SLC1A2 gene;
Gene mutation;
Developmental and epileptic encephalopathy
- From:
Chinese Journal of Neuromedicine
2024;23(11):1140-1147
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the clinical and genetic characteristics of developmental and epileptic encephalopathy (DEE) caused by SLC1A2 gene mutations. Methods:The clinical manifestations, auxiliary examination results, and genetic testing results of a patient with DEE caused by SLC1A2 gene mutations who was treated at Epilepsy Center, Children's Hospital Affiliated to Shandong University on February 6, 2021 were summarized. Cases of SLC1A2 gene mutations were searched using keywords " SLC1A2" and "developmental and epileptic encephalopathy" in CNKI, Wanfang, and PubMed databases, retrieving literature published from the establishment of these databases to September 2024. Bioinformatics analysis was performed; the clinical and genetic characteristics of DEE caused by SLC1A2 gene mutations were summarized. Results:The main manifestations of the patient were rhythmic shaking of the right upper limb or focal motor seizures of bilateral upper limbs, or focal spasm of right upper limb (elevation for once). Ictal electroencephalogram showed 2-3 Hz polymorphic slow waves in the left central area, parietal area and central midline area, affecting the opposite side, or spike rhythm with decreased frequency in the right frontal area, central area and midline area, or polymorphic slow waves in the left central area and central midline area. Whole-exome sequencing indicated a heterozygous de novo mutation in the SLC1A2 gene: c.254T>G/p.Leu85Arg. A total of 7 patients with DEE caused by SLC1A2 gene mutations were retrieved from 5 related literature. All 8 patients (including the patient in our hospital) presented with epileptic seizure, developmental delay, and abnormal EEG; all of them were sporadic cases with de novo heterozygous missense mutations of SLC1A2 gene. Bioinformatics analysis showed that the 4 amino acid residues Gly82, Leu85, Pro289, and Pro333 in the 8 patients were located in the intolerance region of SLC1A2 gene encoding glutamate transporter protein 2 (EAAT2). The 5 amino acid mutations (Leu85Arg, Leu85Pro, Gly82Arg, Pro333Ser, Pro289Arg) in the 8 patients all led to significant changes in number and binding of hydrogen bonds between amino acid residues in EAAT2; except for Gly82Arg mutation, the other 4 mutations could obviously reduce the structural stability of EAAT2. Conclusion:De novo heterozygous missense mutations in SLC1A2 gene can lead to DEE, characterized by developmental delay, EEG abnormalities, and epileptic seizure; these mutations are typically located in critical regions of EAAT2, potentially resulting in reduced protein structural stability.
