ABSTRACT
Objective:To analyze the clinical phenotype, copy number variation, treatment and follow-up characteristics of children with typical 16p11.2 deletion syndrome.Methods:The clinical data of 10 children with typical 16p11.2 deletion syndrome who were treated in the Department of Neurology, Children′s Hospital of Fudan University from August 2011 to December 2021 were retrospectively collected, and their clinical phenotype, copy number variation, treatment and follow-up were summarized.Results:Among the 10 children, 4 are female and 6 are male, all with epilepsy. Nine patients had epilepsy in infancy, and the age of onset was 6.0 (4.0, 8.5) months. Four cases had focal seizures (1 with fever), 4 had generalized tonic-clonic seizures, and 2 had focal seizures with generalized tonic-clonic seizures. Eight cases had cluster seizures (more than 2 to 10 seizures within 24 hours), and 1 case had 1 status epilepticus. Nine children did not show obvious developmental delay at the onset of epilepsy, and 1 child had developmental delay at the onset of epilepsy at 14 months of age. One child had parallel toes at left foot, and 1 had macrocephaly and low limb muscle tone. Genetic testing found that 10 children carried typical 16p11.2 heterozygous deletion, the starting position of the deletion fragment was Chr16:29478119-29675016, the ending position was Chr16:30125670-30206112, and the deletion length was 525-712 kb, all of which were considered pathogenic variants. In the antiepileptic drug treatment, 4 children were treated with oxcarbazepine, 2 with sodium valproate, 2 was switched to oxcarbazepine after levetiracetam was ineffective, 1 with levetiracetam combined with sodium valproate, and 1 with levetiracetam in combination with sodium valproate and ketogenic diet, and all 10 children had no seizures. One patient developed episodic exercise-induced dyskinesia at school age, and the seizures decreased after treatment with oxcarbazepine. Follow-up of 10 children found that 9 children had different degrees of developmental delay (language was significantly affected), 3 cases were combined with autism-like manifestations, and 1 case had poor comprehension, learning difficulties, and repeated grades after entering regular primary schools.Conclusion:The typical 16p11.2 microdeletion syndrome has the deletion of gene fragments in the proximal region of 16p11.2, characterized by drug-responsive cluster seizures with onset in infancy, which may be accompanied by language delay, autism spectrum disorder and nonspecific malformations.
