Developmental epileptic encephalopathies (DEEs) are a group of disorders characterized by early-onset seizures, abnormal electroencephalogram (EEG) patterns, and developmental delay or regression. They are characterized by complex etiology and are often refractory to treatment, severely impacting affected children, particularly infants and toddlers, and pose a challenge in pediatric neurology. In recent years, with the rise of precision medicine, an increasing number of pathogenic genes associated with DEEs have been discovered. However, the specific pathogenic mechanisms and signaling pathways of these genes in the body still require further investigation. This article primarily discusses the genetic patterns of DEEs and the selection of genetic testing, emphasizing the timing of genetic testing assisted by the epilepsy phenotype, especially in DEEs associated with single-gene mutations and new therapeutic drugs, to aid in clinical decision-making for DEEs. It also introduces the use of neurobiological models for DEE research to effectively advance epilepsy research, thereby enabling targeted gene therapy.
ObjectiveTo investigate the clinical electrophysiological characteristics of Cyclin-dependent kinase-like 5 gene induced developmental epileptic encephalopathy (CDKL5-DEE). MethodsThe clinical data and series of video EEGs of children with CDKL5-associated developmental epileptic encephalopathy (CDKL5-DEE) who were admitted to the Children’s Medical Center of Peking University First Hospital from June 2016 to May 2024 were retrospectively analyzed. Results A total of 16 patients with CDKL5-DEE were enrolled, including 13 females and 3 males. All patients had de novo variants of CDKL5 gene, including 6 cases of missense variants, 5 cases of frameshift variants, 4 cases of nonsense variants, and 1 case of large fragment deletion. The age of onset was 8 days (d) after birth ~1 year (y) and 10 months (m), and the median age was (85.94±95.76) days. Types of seizures at onset: 4 cases of tonic seizures [age of onset 10~52 days, median age (25.5±15.84) days]; There were 5 cases of focal seizures [age of onset 8 d~8 m, median age (77.76±85.97) d]. There were 4 cases of epileptic spasmodic seizures [age of onset 3 m~1 y 10 m, median age (6.25±3.49) m]; There were 2 cases of bilateral tonic-clonic seizures [age of onset 30~40 days, median age (35.00±5.00) days]; focal concurrent epileptic spasm seizures 1 case (age of onset 2 m). A total of 59 VEEG sessions were performed in the pediatric EEG room of Peking University First Hospital for 4 hours. All the results were abnormal, including 26 normal background, 25 slow rhythm difference with background, and 8 no background. The interictal was 16 posterior or focal discharges, 19 multifocal discharges, 17 generalized or accompanied by focal/multifocal discharges, and 7 hypsarrhythmia; The ictal was 33 epileptic seizures, 6 myoclonic seizures, 5 focal seizures, 2 tonic-clonic seizures, 2 atypical absence seizures, 2 tonic seizures, 1 myoclonic sequential focal seizure, 1 focal sequential epileptic spasm, and 1 hypermotor-tonic-spasms. The background of patients within 6 months of age was normal, and the background abnormality increased significantly with age. generalized discharges are evident after 2 years of age between seizures. Conclusion CDKL5-DEE seizures have an early onset and are refractory to medications. Epileptic spasms are the most common type of seizure in every patient and long-lasting, with generalized seizures increasing markedly with age. EEG is characterized by a normal background within 6 months. With the increase of age, the background and interictal discharges have a tendency to deteriorate.