The life expectancy of patients with CDKL5 gene mutation varies according to the severity of the disease. CDKL5 gene mutation is a rare disorder, mainly due to mutations in the cytokinin-dependent kinase-like 5 (CDKL5) gene located on the X chromosome, with the main clinical features of refractory epilepsy and severe neurodevelopmental damage. It is usually more prevalent in girls than in boys, and most of the affected children are unable to walk, talk, or eat on their own, and are unable to take care of themselves and need to be cared for by others. As the disease only involves the nervous system, the patient’s condition is relatively mild. Taking the medication on time as prescribed by the doctor and controlling it properly will have no significant effect on his/her life expectancy, but do not change the dosage or the time of taking the medication without authorization. In addition, it should be noted that if the patient’s condition is severe and the treatment is ineffective, it may have an impact on the patient’s life expectancy. In conclusion, how long you can live after CDKL5 gene mutation varies from person to person and from disease to disease. Patients need to maintain a good lifestyle, dietary habits, good care, and prevent complications, which can help prolong life.