For genetic testing, it is proposed to conduct the strong candidate gene sequencing first (SCN1A for Dravet syndrome, MECP2 for Rett syndrome and TSC1/2 for tuberous sclerosis complex) before a NGS multi-gene panel testing [95–97]. The gene discussed is MECP2; the disease is encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.