Abstract: Background：The clinical spectrum of 16p11.2 microdeletion syndrome is highly heterogeneous, and most studies are case reports. Objective：To summarize the clinical features of 16p11.2 microdeletion syndrome with epilepsy as the main phenotype, so as to improve the clinical understanding of this disease. Design：Case series report. Methods：From July, 2017 to October, 2021, children with epilepsy diagnosed as 16p11.2 microdeletion syndrome in the Department of Neurology, Shenzhen Children's Hospital were included. The clinical manifestations, laboratory examination results, EEG and neuropsychological evaluation results, imaging examination reports, treatment and follow-up of children were intercepted from the medical record system. Peripheral venous blood was collected from patients and their parents for the genetic testing. Main outcome measures：Clinical phenotype and genetic abnormality analysis. Results：Totally 11 patients (age range: 336 months; median age: 7 months; male:6, female: 5), were enrolled. All 11 patients presented focal seizure as the early symptom. There are 8 cases of language retardation and 2 cases of motor retardation (including 1 case of paroxysmal motorinduced dyskinesia). By EGG, 8 patients were found having intermittent discharge while the other 3 patients had normal EGG backgrounds, and by brain MR imaging, 1 case of abnormal white matter signal was observed. The 11 cases of 16p11.2 microdeletion showed a deletion of 524908 kb and 8 of them were de novo mutations. The overlapping region chr16:2967499130199601 contains 27 proteincoding genes and 6 of them are diseaserelated OMIM genes. Only PRRT2 was well evidenced to be haploinsufficient, which causes benign infantile epilepsy. Epilepsy was easy to control in all these patients. Nine cases were treated with antiepileptic drugs, including monotherapy of oxcarbazepine, sodium valproate or topiramate (n=8) and combination therapy of phenobarbital and levetiracetam (n=1). Paroxysmal motorinduced dyskinesia occurred after the combination therapy cure the disease and was stopped, but it did not happen again after the oxcarbazepine treatment. Conclusion：16p11.2 microdeletion syndrome is one of the potential causes of epilepsy, which should be paid attention to in genetic evaluation. For children with 16p11. 2 microdeletion syndrome, dynamic neuropsychological evaluation is needed and attention should be paid to PKD symptoms so as to make timely diagnosis and treatment.

Key words: Epilepsy, 16P 11.2 deletion syndrome, Children