Clinical features and treatment efficacy in cdkl5 mutation-related epileptic encephalopathy in the infant

Purpose: Mutations in the cyclin-dependent kinase-like 5 (CDKL5) gene are associated with epileptic encephalopathy and severe cognitive impairment. We aim to characterize the association between this gene and treatment efficacy. Methods: We retrospectively analyzed 10 patients who were treated at Severance Children's Hospital for epileptic encephalopathy who were subsequently diagnosed with a CDKL5 mutation using next-generation sequencing. Results: Electroencephalography (EEG) results showed generalized pattern abnormalities in 60% (6/10) of patients with CDKL5 mutations. We analyzed the effects of three treatments, namely antiepileptic drugs (AEDs), ketogenic diet (KD), and steroids. A more than 50% reduction in seizures was observed in 12% (1/8) of patients treated with clobazam. KD treatment proved inef-fective in most cases. In addition, a more than 50% reduction in seizures was observed in 57% (4/7) of patients treated with steroids. EEG analysis of patients treated effectively with steroids revealed that 75% (3/4) showed hypsarrhythmia and 25% (1/4) showed focal epileptiform. Conclusion: In this study, as in other studies, AEDs and KD did not effectively control seizures in most patients with a CDKL5 mutation. However, steroid therapy reduced the frequency of seizures in patients who also exhibited hypsarrhythmia. This suggests that steroid treatment is help-ful in cases of hypsarrhythmia with CDKL5 mutations.