Clinical phenotype and genetic analysis of children with developmental epileptic encephalopathy type 17 caused by GNAO1 gene mutation
10.3760/cma.j.cn113694-20250117-00038
- VernacularTitle:GNAO1基因变异致发育性癫痫脑病17型患儿的临床表型及基因分析
- Author:
Daoqi MEI
1
;
Yu GU
;
Shiyue MEI
;
Bingbing ZHANG
;
Liya ZHANG
;
Manli WANG
;
Yan LI
;
Jihong TANG
Author Information
1. 苏州大学附属儿童医院神经内科 儿童癫痫中心，苏州 215025
- Publication Type:Journal Article
- Keywords:
Epilepsy;
Motor disorders;
Developmental epileptic encephalopathy;
GNAO1 gene;
Missense mutation;
De novo variation
- From:
Chinese Journal of Neurology
2025;58(9):971-980
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To summarize the clinical characteristics of 5 children with developmental epileptic encephalopathy type 17 (DEE17) caused by GNAO1 gene variants confirmed by whole-exome sequencing and analyze the features of their genetic variants. Methods:A retrospective analysis was conducted on the clinical data of 5 children diagnosed with GNAO1-related DEE17 in the Department of Neurology, Children′s Hospital of Soochow University from January 2019 to October 2024. Their clinical features, genetic testing results, neuroimaging findings, electroencephalogram (EEG) results, and treatment regimens were summarized. Follow-up was performed via telephone or outpatient visits. Results:Among the 5 diagnosed children (3 males, 2 females), the age of onset ranged from 2 days to 2 years, and the age at diagnosis ranged from 2 days to 6 years. Four children presented with seizures in the neonatal or infantile period, manifesting as hypotonia, developmental delay, and seizure types including generalized tonic-clonic, myoclonic, and epileptic spasms. One child had a later onset at 2 years, presenting with language delay, intellectual disability, and involuntary movements, followed by seizures at 6 years, including focal and generalized tonic-clonic seizures. Genetic testing revealed de novo heterozygous missense variants in GNAO1 in all 5 cases: c.119G>C (p.G40A), c.808A>C (p.N270H), c.808A>G (p.N270D), c.118G>C (p.G40R), and c.17G>T (p.S6I). Among these variants, c.119G>C and c.17G>T were previously unreported pathogenic variants. Neuroimaging showed nonspecific changes in 3 children (widened frontal-temporal subarachnoid space, delayed myelination) and abnormal white matter signals in 2 cases. Long-term video-EEG revealed abnormal discharges and background slowing in all cases: multifocal discharges in 4 cases and focal epileptiform discharges (left mid-temporal) in 1 case. Clinical seizures were captured in 3 cases: 1 with a burst-suppression pattern and 2 with hypsarrhythmia. All patients received 3 or more antiseizure medications. Four cases (cases 1-4) responded well to topiramate combination therapy, with 2 cases (cases 1, 2) achieving complete seizure freedom and 2 cases (cases 3, 4) experiencing more than a 50% reduction in seizures. One child (case 3) achieved seizure control with an adjunctive ketogenic diet. The late-onset case (case 5) required a combination of levetiracetam, oxcarbazepine, and valproate for seizure management. Conclusions:GNAO1 variants can lead to DEE17 with diverse seizure types, often requiring multiple antiseizure medications, among which topiramate is effective. Early-onset cases typically present with seizures and developmental delay, while late-onset cases may exhibit language delay, intellectual disability, movement disorders, and refractory epilepsy. Genetic testing should be performed early for timely diagnosis.
